The impacts of climate change on human health in Texas

Carlota Santos

The Impacts of Climate Change on Human Health

in Texas

SOCIO-ECONOMICS GROUP

HARTE RESEARCH INSTITUTE

June 2010

Climate Change and Human Health

The Impacts of Climate Change on

Human Health in Texas

By:

Carlota Santos

David Yoskowitz, PhD

With Assistance provided by:

Emily Williamson

Report funded with a Grant by the Energy Foundation

Harte Research Institute for Gulf of Mexico Studies

Texas A&M University- Corpus Christi

6300 Ocean Drive,

Corpus Christi, Texas 78412

Suggested Citation: Santos, C. and D.W. Yoskowitz, 2010. The Impacts of Climate

Change on Human Health in Texas. Harte Research Institute. June. 54 pages.

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Table of Contents

Executive Summary……………………………………………………………………….1

I. Introduction………………………………………………………………………..4

II. Human Health and the Impacts of Climate Change……………………………….5

1. Physical Effects……………………………………………………………7

2. Physical/Chemical Effects……………………………………………….15

3. Physical/Biological Effects………………………………………………18

4. Sociodemographic Effects…………………………………………….....26

III. Climate Change and Human Health in Texas……………………………………29

1. Texas Air Pollution, Human Health, and Climate Change………………29

2. Water Supply, Water Quality, and Climate Change in Texas…………...30

3. Climate Change Impacts in Texas……………………………………….32

IV. Mitigating Climate change: costs and benefits…………………………………..37

1. Costs of Inaction…………………………………………………………37

2. Costs of Climate Mitigation……………………………………………...38

3. Benefits of Climate Mitigation………………………………………......42

V. Conclusion……………………………………………………………………….47

References……………………………………………………………………………….51


Executive Summary

This report talks about the impacts of Climate Change in Human Health, including the costs of inaction and the costs and benefits of climate mitigation actions.

People are exposed to climate change through variations in weather phenomenon such as temperatures, sea-level rise, precipitation, and more frequent extreme weather incidents (IPCC, 2007). According to the IPCC’s report, the major impacts climate change can have on human health include: • temperature-related illness and death • extreme weather-related health consequences • air pollution-related health effects • water and food-borne diseases • vector-borne and rodent-borne diseases • effects of food and water shortage • Mental, nutritional, infectious and other health incidents.

To better understand the impacts of climate change on human health, Patz et al. (2000) classifies the harmful exposures as physical, physical/chemical, physical/biological, and sociodemographic (Patz, Engelberg, & Last, 2000).

Physical effects include number of hot days, extremely cold days, urban island effect, extreme weather events, floods, severe storms, and droughts. These extreme events overwhelm the capacity of people to cope with the situation and produce widespread losses throughout various economic sectors. Physical/chemical effects include air pollutant formation and transport and release of toxic chemicals. Physical/biological effects involve disease agents, vectors, and their habitats, altered marine and freshwater ecology, altered food productivity, nutrient value, plant pathogens, and effects on levels of aeroallergens. Sociodemographic effects include forced displacement, overcrowded living conditions, and human conflicts. Forced migration can be a result of sea level rise and repeated flooding.

In Texas, some of the impacts climate change will have on the population health include:

• More frequent and severe attacks of asthma, an increased occurrence of strokes, and aggravation of other respiratory illnesses and cardiac problems.

• Changes in quality and supply of freshwater. • More accidents and injuries caused by extreme weather events. • Higher health risk for vulnerable populations. • Higher risk of infectious diseases. • Increased number of heat-related illnesses. Two high risk areas in Texas are the Texas-Mexico border region and Texas

coastline. The Texas-Mexico border region has poor air quality and sewer systems and 12% of its population does not have access to clean water. The Gulf coast is one of the most vulnerable areas to climate change in the state and that puts the Texas coastline at high risk as well. Any change that affects the sea, whether it’s the water temperature, wind, currents, nutrient levels, or precipitation level, is of concern to the Texas coast.

Overturning climate change requires immediate action. Its impacts are long-term and continual and mitigation actions should include numerous ethical perspectives such as justice and equity, rights, freedom, and welfare. While there may be some uncertainties

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about climate modeling, it is clear that human activities have a powerful effect on climate (Stern et al., 2007).

Cost of Inaction Climate change and its consequences on human health will have and is already

having significant economic impacts in Texas. More frequent and severe weather extremes and more recurrent transmitted infectious diseases will increase mortality, morbidity, and injuries. More money will be spent on human health. Worldwide, from 1980 to 2004, the economic costs of weather-related natural events were US$ 1.4 trillion (in 2004 US dollars) (Anderson et al., 2005). With climate change, these costs are likely to increase.

Costs of Climate Mitigation Climate change and the severity of its impacts will continue to rise unless the

emission of greenhouse gases is reduced or stabilized. Firm action is needed to delay, stop, or overturn the continuous rise of greenhouse gas emissions (House of Lords, 2005).

Stabilization means reducing annual emissions to the levels that balance the Earth’s natural capacity to remove greenhouse gases from the atmosphere. In the long run, emissions will have to be reduced by 80% of current levels to reach stabilization. The longer before actions are taken, the more drastic the changes will have to be (Stern, 2007). There are several possible emission trajectories with early or late peaks and more gradual or drastic cuts. However, higher cuts have been historically associated with economic recession or turmoil (Stern, 2007). Seeing this, it would be beneficial for Texas to start stabilizing GHG emissions now since later actions are more risky and less economically viable.

Benefits of Climate Mitigation Slowing down or stopping the course of climate change would result in benefits for

human health directly related to decreases in temperature and associated impacts. Climate policies aimed at reducing greenhouse gas emissions would also improve air quality and other ancillary health benefits. Whereas the benefits from climate policies would be felt over the long-run, the ancillary health benefits would be felt in the short-term (Bell et al., 2008).

Ancillary benefits are the side effects of mitigating problems such as air pollution. Sometimes they are called ancillary impacts, meaning they can be positive or negative. To make the comparison of benefits or impacts easier, the outcomes are usually converted into economic terms that allow direct comparison between costs and benefits. One way of estimating economic benefits or costs is by attributing a value for saved lives (VSL). The global economic value of loss of life due to climate change ranges from $6 billion to $88 billion, in 1990 U.S. dollar prices (Confalonieri et al., 2007).

In the United States, the potential number of lives saved annually by reducing air pollutants equals the number of deaths from HIV or infectious liver diseases in 2000 (note that the study used a very conservative approach (World Resources Institute, 1997).

Consequently, numerous measures are being addressed by several entities and countries to adapt to climate change (Anderson et al., 2005). Texas should adopt and lead such initiatives. Balancing actions that decrease vulnerabilities and facilitate climate’s

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stabilization should be a standard that can guide public policy, private investment, and insurance policies in Texas.

The first section of this report will talk about the impacts of climate change in human health. In the second section, the impacts on Texas specifically will be discussed, such as the most vulnerable areas and population. This will be followed by the costs of inaction. The next section will focus on the costs of climate mitigation and lastly the report will conclude with the benefits of early climate mitigation actions.

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I. Introduction Human health is expected to be affected by current climate change (IPCC, 2007).

Increased temperatures and weather variability have already brought higher probabilities of category four and five hurricanes and sea level rise. Given that CO2 emissions remain in the atmosphere for roughly 100 years and those same emissions are unlikely to decrease, the negative health impacts of climate change are likely to persist or increase if no action is taken (Luber & Hess, 2007). People are exposed to climate change through variations in weather phenomenon such as temperature, sea-level rise, precipitation, and more recurrent extreme weather incidents. Cold causes hypothermia, heat hyperthermia, and drought famine. Floods, tornadoes, hurricanes, and forest fires can cause displacement, injuries and eventually death (Frumkin, et al., 2008). Indirectly, humans are affected through variations in air and food quality, water availability, and changes in the ecosystems, industry, agriculture, and in the economy (IPCC, 2007).

Climate change has already modified the geographical distribution of some allergenic pollen species, the distribution of some infectious disease vectors, and increased number of deaths related to heatwaves (IPCC, 2007). According to the same IPCC report (2007) the major health effects brought by climate change include: • temperature-related illness and death • extreme weather-related health consequences • air pollution-related health effects • water and food-borne diseases • vector-borne and rodent-borne diseases • effects of food and water shortage • Mental, nutritional, infectious and other health incidents.

The different ways climate change can affect human health are depicted below.

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Figure 1: Pathways through which Climate Change can affect Human Health.

Source: WHO, 2008.

To respond to changes in the climate system, humans need to improve their adaptive capacities. Those at higher risk of suffering from climate change are the elderly, the urban poor, children, coastal populations, subsistence farmers, and traditional societies (IPCC, 2007). II. Human Health and the Impacts of Climate Change

Human health consists of physical, social and psychological well-being. It depends on sufficient food, safe drinking water, secure shelter, and good social circumstances (WHO, 2008). Changes in the climate system can affect human well-being and safety conditions, directly or indirectly, and cause disability, suffering, and potentially death (IPCC, 2007).

Human health has improved considerably since the 1950s, yet there are still many inequalities within and among different countries. The vulnerability of human health to weather and climate is based on five basic ideas: (1) the fact that extreme events affect human health, (2) climate can be the reason for the distribution of a disease or disease vector, (3) interannual climate variance affects human health, (4) studies on vector, plant, or pathogen biology are important, and (5) the effectiveness of public health procedures to protect people’s health from climate exposures (IPCC, 2007).

Some findings about climate change and human health have been given by IPCC’s assessments on climate change. According to its Third Assessment, heatwaves are associated with risk of mortality and morbidity, especially among the elderly and urban poor. Climate extremes such as storms, droughts, and floods associated with climate

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change may cause injuries and deaths, population displacement, undesirable consequences on freshwater availability and quality and on food production, and increase the probability of spreading infectious diseases (IPCC, 2001). Climate change may also cause economic decline, social disturbance, and population dislocation. Variances in world food production may increase the number of undernourished populations, especially in poor countries. Lastly, if global emissions of CO2 remain constant, air quality will deteriorate especially in urban areas. Exposures to such gases can increase mortality and morbidity (IPCC, 2001).

Major health concerns involving climate change include fatalities and injuries related to heat waves and extreme weather events, infectious diseases related to variations in vector biology, water and food contamination, allergies due to increased allergen production, cardiovascular and respiratory disease related to an increase in air pollution, and nutritional deficiencies due to changes in food production (Frumkin, Hess, Luber, Malilay, & McGeehin, 2008). Besides the negative impacts, warmer conditions can also bring some benefits. With warmer temperatures, fewer winter deaths can occur in temperate climates, increases in food production especially in high latitude regions may occur, and some changes in the range and transmission of malaria in Africa may also occur (WHO, 2008; IPCC, 2007). Nevertheless, negative consequences of global warming are expected to outweigh its benefits (IPCC, 2007). Additionally, the U.S population is aging and this means that more people will be more vulnerable to the health impacts of climate change. The figure below illustrates the trend from 2000 to 2100 (Kristie L. Ebi, Mills, Smith, & Grambsch, 2006). Figure 2: Trends in the U.S. Population from 2000 to 2100

Source: Ebi, 2006. To better understand the effects of climate change on human health we classify

harmful exposures as physical, physical/chemical, physical/biological, and sociodemographic (Patz et al., 2000). Physical effects include the number of hot days, number of cold days, urban island effect, extreme weather events, floods, severe storms, and droughts. Physical/chemical effects include air pollutant formation and transport and release of toxic chemicals. Physical/biological effects involve disease agents, vectors, and their habitats, altered marine and freshwater ecology, altered food productivity, nutrient value, plant pathogens, and effects on levels of aeroallergens. Lastly, sociodemographic effects include forced displacement, overcrowded living conditions, and human conflicts (Patz et al., 2000). In the next section, the impacts of climate change on Human Health will be described.

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1. Physical Effects Physical events include any extreme weather event with periods of very high or low

temperature, heavy flooding and rain, storms, and droughts. Although populations develop physiological, cultural, behavioral, and technological responses and adaptations to climate systems, extreme weather events usually stress people beyond their adaptation levels (A. J McMichael, Woodruff, & Hales, 2006). Extremes can be divided into five different categories: biological, geophysical, climatological, hydrological, and meteorological. These different categories are illustrated in the figure below (Scheuren, le Polain de Waroux, Below, Guha-Sapir, & Ponserre, 2008). Figure 3: Natural Disasters.

Source: (Scheuren et al., 2008).

Extreme weather events overwhelm the capability of people to cope with situations

and produce widespread losses throughout various economic sectors. Damages may occur to infrastructures and houses, industries, agriculture, tourism, and the environment. Losses felt in all these sectors can affect the populations’ livelihoods and potentially set back the economy (Below, Grover-Kopec, & Dilley, 2007). On average, extreme weather incidents caused ~123,000 deaths between 1972 and 1996 (Patz et al., 2000). For every person that dies on such events, 1,000 are affected either directly or indirectly. Population well-being can also be damaged by post-traumatic stress disorder (PTSD) or other type of mental disorder. The intensity and unexpectedness of the disaster will determine its impact on the population (Patz et al., 2000).

Current climate trends suggest more warm days and fewer cold nights. Average seasonal temperature involves an increase in the number of heatwaves in the summer and a decrease in the number of cold nights. This may lead to more daily deaths and diseases on those hot summer days and fewer winter deaths and diseases in temperate countries (Patz, 2000). Consequences of a hot day are felt for only a few days, while cold days can last up to two weeks (McMichael et al., 2006). Extreme Weather Events

Exposure to both extreme hot and cold weather is linked with morbidity and mortality, compared to moderate and comfortable temperatures (Patz et al., 2000). Humans usually exhibit an optimum temperature at which mortality rate is the lowest. Death rates increase when temperatures reach levels outside this comfort zone (A. J McMichael et al., 2006).

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Figure 4: Relationship between temperature and temperature-related deaths

Source: McMichael et al., 2006.

Extreme weather events include the occurrence of heat waves, cold waves, floods,

droughts, severe storms, and rapid sea level rise. Heat Waves: Can cause heat stroke and cardiorespiratory failure. There is no universal standard definition for heat wave, but the Netherlands

meteorological bureau defines it as lasting at least five days with temperatures above 25˚C and at least three days of those five with maximum temperatures of more than 30˚C (Figure 5; McMichael, 2003). Although heatwaves can kill, the degree of temperature-related mortality varies significantly by latitude and climatic zone (McMichael, 2006; Patz, 2000; McMichael, 2003). As an example, the comfortable temperature in Taiwan is 29˚C versus 16.5˚C in the Netherlands (Patz et al., 2000). People in warmer cities are more affected by colder temperatures and people in colder cities are more affected by higher temperatures (A. J McMichael et al., 2006). Indeed, in subtropical and temperate countries, seasonal death rates are highest in winter season, especially from cardiovascular disease (Patz et al., 2000).

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Figure 5: Extreme temperature days.

Source: McMichael et al., 2006.

Death risks also increase when thermal stress lasts for several consecutive days

coupled with hot nights (Patz et al., 2000). Daily temperature related deaths increase during heatwaves. Although heatstroke and heat exhaustion are directly linked with high temperatures, the majority of deaths as a consequence of heatwaves are related to cerebrovascular, cardiovascular and respiratory disorders (Campbell-Lendrum et al., 2003; Patz et al., 2000). Heat stress can trigger vascular events such as heart attack or stroke (Campbell-Lendrum et al., 2003). Change in blood pressure, cholesterol, blood viscosity, and heart rate related to physiological response to temperature variances are one reason for an increase in cardiovascular disease and associated mortality (Patz, 2000). Short-term mortality displacement is also common during heatwaves. Its proportion depends on the intensity of the heat wave and the health status of the population affected (IPCC, 2007).

Heat waves, hot days, and hot nights have become more recurrent (IPCC, 2007). In India, 18 heat waves were reported between 1980 and 1998. One of those heat waves caused 1,300 deaths (Patz et al., 2000). In Chicago, USA a heat wave in July 1995 caused 514 deaths and 3,300 excess emergency consultations (Campbell-Lendrum et al., 2003) In Europe in 2003, a severe heat wave caused over 35,000 deaths (WHO, 2007; McMichael et al., 2006) and high temperatures account for about 0.5-2% of annual mortality among elderly (IPCC, 2007). Figure 6 illustrates the lethality of such events.

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Figure 6: Number of Weather Events, people killed, and affected by region of the world for the 1980's and 1990s.

Source: McMichael et al., 2003

Additionally, factors that increase the intensity of heatwaves are the “urban island

effect” (when interior urban areas with high thermal accumulation and low ventilation absorb and preserve the heat) and the lack of air conditioning and poor housing conditions, which are common in urban populations and developing countries (McMichael et al., 2006). The elderly, the young, people with impaired mobility, and those suffering from cardiovascular diseases are at higher risk due to their limited physiological capacity to adapt (Patz et al., 2000; McMichael et al., 2006). Moreover, many developed countries have an aging population, which increases the population at risk from suffering from temperature changes (Patz et al., 2000). According to McMichael et al. (2003), the main factors of vulnerability to temperature-related mortality are:

• Age, gender, and disease profile • Housing conditions • Socioeconomic status • Pre-valence of air conditioning • Behavior (ex. clothing)

Cold Waves: Can cause cerebrovascular, cardiovascular, circulatory, and respiratory

diseases. In some temperate countries, winter mortality is 10-25% higher than summer

mortality. Some of the major causes for these cold deaths are cerebrovascular, cardiovascular, circulatory, and respiratory disorders (McMichael et al., 2003). In northern latitudes, cold waves remain a problem since extremely low temperatures can be reached in a few hours and last for a long period. Cold exposure usually occurs outdoors and among workers, socially deprived people, and the elderly in temperate and cold environments (IPCC, 2007). Behavioral and social adaptations to cold are very important to decrease winter deaths, especially in high latitude regions. Sensitivity to cold weather can be quantified as the percentage increase in mortality per 1˚C decrease in temperature (McMichael et al., 2003). Living in cold climates is associated with significant risk of hypothermia and frostbite (IPCC, 2007) and the elderly (75 years old or older) are predominantly vulnerable to winter death (McMichael et al., 2003). In countries well

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prepared for cold temperatures, increases in mortality can still occur if electricity or heating systems fail. Cold waves can also affect people in warmer climates like in south-east Asia (IPCC, 2007). Nevertheless, with warming temperatures, it is expected that winter mortalities will decrease slightly. A British study suggests that approximately 9,000 fewer cold-related deaths will occur annually by 2040 in England and Whales (Patz et al., 2000). According to this, warming temperatures can actually bring some benefits and reduce mortality in cold climates. Physiological and behavioral adaptations, as well as public health preparedness, can reduce temperature-related deaths. Adaptations to climate change such as air conditioning, improved health care, and public awareness can also reduce the health risks (McMichael et al., 2006).

There has been great improvement in the techniques to quantify heat and cold health effects, including identifying any medical, social, or environmental factor that may influence temperature-related mortality (IPCC, 2007). A population’s sensitivity to temperature extremes has varied between decades, but there is some evidence that the U.S. population became less sensitive to high temperatures from 1964 to 1988 (IPCC, 2007). Until now it has been challenging to quantify the role of air conditioning in decreasing heat-related mortality, but some studies have reported a decrease in mortality of 21 to 98% due to access to areas with air conditioning (R. E. Davis, Knappenberger, Novicoff, & Michaels, 2002). Urban and suburban planners have also been taking into consideration heat loads when designing their projects, including more shaded areas and easier access to drinkable water. Human biophysical acclimatization to high temperatures can also be a reason to the decrease in heat-related mortality (R. E. Davis et al., 2002). Cold related deaths have also decreased and cold days, cold nights, and frost days have become more infrequent. In general, people more sensitive to cold temperatures are those living in temperate climates, where populations are generally less adapted to cold (IPCC, 2007).

Floods: Can cause injuries, drowning, deaths and other diseases (infectious, mental, and health disorders).

Floods are low probability, high-impact events that overpower physical infrastructure, human resistance, and social organization. Floods are the most frequent of all extreme natural weather events and between 1992 and 2001 caused approximately 100,000 deaths (IPCC, 2007; McMichael et al., 2006). The trend seen in higher-income countries is leading to increased risk of suffering from flooding. People are moving closer to the coast, along with the world’s topographic profile of deltas and coral reefs, meaning that many settlements and arable land will have a higher risk of flooding from sea level rise. Floods have been intensifying and climate change may contribute even more for this intensification (McMichael et al., 2006).

Consequences of flooding to human health include deaths, injuries, morbidity, infectious diseases, toxic contamination, and mental health disorders. Recorded fatalities from floods are usually from drowning (most of the times) and serious injuries. Deaths from unsafe and unhealthy conditions following flooding are also hazardous to human health, but usually are not accounted for in disaster statistics (IPCC, 2007).

An assessment of floods suggests that in the past 100 years the major events occurred in a limited number of regions. South Asia and Latin America have been the areas which were most affected (IPCC, 2007). As shown in table 1, some of the health consequences

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arise during or right after the flooding had occurred (injuries, communicable diseases, or toxic contaminants) and these are called immediate effects (Patz, 2000). Other health consequences occur afterwards (mental health disorders and malnutrition) and they are called medium or long-term effects (McMichael et al., 2006; Patz et al., 2000).

Table 1: Immediate and Medium/Long-Term Health consequences derived from Flooding Immediate Effects Medium/Long-term Effects Injuries Mental Health Disorders Communicable Diseases Malnutrition Toxic Contaminants Water-borne Diseases Vector-borne Diseases Respiratory Diseases Source: IPCC, 2007.

Extreme rainfall facilitates entrance of human sewage and animal wastes into

drinking water supplies and streams, which lead to medium or long-term effects. Such health effects include water-borne diseases, vector-borne diseases from stagnant water, increase in respiratory diseases from crowded places and limited shelter, malnutrition, and dissemination and release of toxic chemicals from storage and waste disposals (Patz et al., 2000; McMichael et al., 2006). Some consequences of recent flooding have been recorded. In central Europe in 1997, river flooding led to more than 200,000 homeless people and more than 100 deaths. Climate change most likely will lead to an increase in flooding, meaning even higher risks for human health (Patz et al., 2000). Studies have shown that anthropogenic activities influencing climate change are likely in some regions to make a “very wet winter” (seen frequently in the UK) or a “very wet summer” (commonly seen in the South Asian monsoon region), around five times more frequent during the second half of this century (WHO, 2008). Around the globe, climate change is likely to increase the areas affected by flooding (WHO, 2008).

Droughts: Can cause famine, malnutrition, impairment of child growth and

development, burns, post traumatic stress disorder (PTSD), chronic obstructive pulmonary disease (COPD), and asthma.

According to McMichael et al. (2003), there are four types of droughts, described on the table below.

Table 2: Different Types of Droughts

Types of Drought Characteristics Agricultural The amount of moisture in the soil is not

sufficient for crops under cultivation Hydrological Groundwater and surface water levels are

below the usual levels Socio-economic The insufficiency of water affects the

economic ability of people to survive Meteorological Measured precipitation is below normal

levels for a certain region

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Source: McMichael et al., 2003. When a drought occurs, the amount of loss depends on two factors: degree of societal

exposure and vulnerability of those exposed (people, economic activities, and infrastructure). Drought impacts are particularly severe in countries that rely on subsistence agriculture and primary sector activities (i.e. food deficit countries) (Below et al., 2007). Droughts are characterized by their duration, timing, magnitude, and location. They are slow, long lasting, and spatially extensive when compared to other extreme weather events. Direct impacts include water shortages, agricultural losses, and reduced water supply. Indirect impacts include decreased export income, losses to industry, and an increase in payments for imports. All of these may result in macroeconomic impacts (Below et al., 2007).

Health impacts derived from droughts occur mostly from food production. Famine may occur, usually when there is a pre-existent condition of malnutrition, as well as malnutrition (McMichael et al., 2003). Marasmus, a form of protein-energy malnutrition characterized by energy deficit leads to weakness, anorexia, cachexia, and eventually death. Various food shortage-related deaths are associated with infection through a weakened immune system and insufficient clean water for hygiene purposes (Patz et al., 2000). When there is water scarcity, water is usually used to cook and not for personal hygiene. This can lead to diarrheal diseases due to fecal contamination and water-washed diseases, like trachoma and scabies. Malaria can also occur because of changes in vector breeding sites and malnutrition increases the risk for such diseases (McMichael et al., 2003). Moreover, micronutrient deficit, such as lack of vitamin A, can result in respiratory and gastrointestinal diseases (Patz et al., 2000).

Although more severely felt in developing countries, droughts also affect developed countries. According to the U.S. Federal Emergency Management Agency (FEMA), droughts in the U.S. cause to $6 to $8 billion in damages and losses every year. Yet, the high proportion of a drought’s indirect damages versus its direct damages can lead to an underestimation of its economic impacts. Drought-related deaths, for example, are an indirect consequence of population livelihoods and contribute to limited food supply, problems with water and sanitation, poor health conditions, and diseases (Below et al., 2007). Another event associated with drought is drought-induced wildfire, which can cause direct injury and affect air quality (Patz et al., 2000). Direct effects on human health include burns and smoke inhalation (McMichael et al., 2003). Fire smoke holds several fine particles that aggravate respiratory or cardiac problems, such as asthma and chronic obstructive pulmonary disease (Patz et al., 2000). Loss of vegetation, on the other hand, may result in soil erosion and a higher risk of landslide.

Severe Storms Severe storms, with their violent nature, can cause serious morbidity, mortality and

property loss. Some examples of severe storms include hurricanes, tropical storms, and tornadoes (Patz et al., 2000). Impoverished populations living in high-density low-lying and environmentally ruined areas are the most vulnerable to severe storms (McMichael et al., 2003). In tropical regions, extreme winds bring death and damage. There is also evidence of an increase in the frequency of this type of storms in recent decades and this trend is most likely to continue. Studies show that doubling current CO2 levels in the atmosphere, which is expected within 80 years, will lead to an increase of 6% in mean

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cyclone windspeed and a 300% increase in the frequency of the largest storms (category five hurricanes) (WHO, 2008).

Health impacts of severe storms can be exemplified by a 1991 cyclone that hit a low-lying, densely populated area in Bangladesh. It affected approximately 10 million people, killed 138,000, wounded 460,000, and destroyed 1.63 million homes (Patz, 2000). Historical evidence shows that hurricanes are only formed in areas where sea temperatures are above 26˚ C (Patz, 2000). As such, American states bordering the Gulf of Mexico have seen 40 hurricanes since 1990. Of those 40, 16 hit Texas (Grammatico, 2009)(Grammatico, 2009)(Grammatico, 2009)(Grammatico, 2009)(Grammatico, 2009). Additionally, a slight increase of more than 2˚C in sea temperature will lead to an increase of 5% to 12% of hurricane windspeed (Patz et al., 2000), which will make hurricane impacts even more deadly.

Sea level Rise: Can cause population displacement, lost livelihood, exposure to coastal storm surges and floods, and salinisation of freshwater and coastal soil.

Warming temperatures lead to sea level rise. A 1-m sea level rise would inundate low-lying areas and distress 13 million people in Bangladesh, 18.6 in China, 3.3 million in Indonesia, and 3.5 million in Egypt. Continuing see level rise will lead to more severe and frequent coastal flooding and by consequence, more homes and communities will be destroyed and affected and people will seek safer places to live. This increase in migration will raise social and environmental pressures (Patz et al., 2000).

Trends in weather adversities There is an increase in negative impacts of natural disasters; the number of people

affected, injured, or killed by natural disasters is increasingly disturbing (McMichael et al., 2003). Natural catastrophes have more than tripled since the 1960s. In 2007, 14 out of 15 emergency assistance appeals were for droughts, floods, and storms and this number was five times higher than in any previous year (WHO, 2008).

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Figure 7: Number of Weather-related disasters and number of victims during 1975-2007.

Source: World Health Organization, 2008

One of the causes for this increase in weather adversity is population growth and its

concentration in high-risk areas such as cities and coastal zones (McMichael, 2003). Some cities are built on land which is propitious to frequent flooding. In many places, the only available land for poor populations are those with few natural defenses against extreme weather events. To aggravate this situation, there has recently been high migration of people to cities and more than half of the world’s population lives now in urban areas. This places even more people in the path of extreme weather disasters and when it hits urban areas, there are always significant losses involved (McMichael et al., 2003; WHO, 2008). Thus, due to an increase in population vulnerability, even if extreme weather events do not increase in number, its consequent costs and losses will (McMichael et al., 2003).

In conclusion, the increasing trend of extreme events is partially due to more frequent reporting and increased vulnerability of populations. Migration, poverty, and population growth are the major causes of this increase in vulnerability (McMichael et al., 2003).

2. Physical/Chemical Effects: Weather and Air Pollutants Weather determines, influences, transports, and diffuses concentrations of many

pollutants (IPCC, 2007; Patz et al., 2000). Oftentimes, large high-pressure systems create a temperature inversion that traps pollutants in the Earth’s atmosphere (Patz et al., 2000). Air pollution is generally associated with motionless or slowly migrating anticyclonic or high pressure systems that reduce pollution dispersion and diffusion. Airflow alongside those systems can carry ozone signs, creating the necessary conditions for an ozone occurrence (IPCC, 2007).

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Ozone Levels Rising temperature of the troposphere, coupled with Ultraviolet (UV) radiation, boosts

photochemical reactions that produce secondary oxidants like ground level ozone (Patz et al., 2000). Ground-level ozone occurs both naturally, as the main source of urban smog, and through photochemical reactions involving nitrogen oxides and unstable organic composites when accompanied by sunshine and high temperatures (IPCC, 2007). In cities, transport vehicles are the main source of both unstable organic composites and nitrogen oxides. Wind, temperature, atmospheric moisture, and solar radiation together affect the production of ozone (IPCC, 2007). Thus, increasing air temperatures will increase levels of air pollutants such as ground-level ozone, especially in regions already polluted (WHO, 2008).

Ozone concentrations are typically higher during the summer because its production depends on sunlight. Nevertheless, not all urban areas have seen such seasonality. Concentrations of ozone levels are increasing in most regions and exposure to higher concentrations is linked to more hospital admissions for chronic obstructive pulmonary disease, pneumonia, asthma, allergic rhinitis, and premature mortality (IPCC, 2007).

Contact with ozone intensifies asthmatics’ sensitivity to allergens and weakens lung function, mostly among the elderly and children (Patz et al., 2000). Annually, air pollution causes 800,000 deaths, particularly from cardiovascular and respiratory diseases (WHO, 2008). In London, the most consistent cause for respiratory diseases for patients admitted in hospitals was ozone, with the strongest effects occurring during the warmest season. In Mexico, ozone was associated with a rise in hospital admissions for asthma and lower respiratory infection in children (Patz et al., 2000). Major determinants of ozone exposure are outdoor ozone concentrations, housing characteristics, such as the degree of insulation, and activity patterns (IPCC, 2007).

Higher temperatures Global warming can increase the concentrations of air pollutants, such as fine

particulate matter (PM) and ozone, and the frequency of such occurrences, since its production depends on temperature and humidity (Patz et al., 2000; IPCC, 2007). A 1˚C rise in temperature of ozone may increase global deaths due to air pollution by more than 20,000 annually (WHO, 2008). In Europe and eastern United States, the majority of days in which ozone levels surpass air quality standards occur when high-pressure systems are moving slowly which happens around the summer solstice. During this period, sunlight is at its highest, solar radiation is most intense, and air temperatures are elevated (Patz et al., 2000).

During 1995, one of the hottest years recorded, 71 million Americans (32% of the population) were living in counties where ozone levels surpassed the EPA’s national Ambient Air Quality Standards. Occurrences of high levels of ozone last, on average, for three to four days over an extended area, that is, an area of more than 600,000 km2. Estimations of climate change influence on air quality are still limited. Nevertheless, most studies found that ozone formation is higher with higher temperatures, but UV flux can be a stronger determinant than high temperatures (Patz et al., 2000).

Contemporaneous hot weather and air pollution can have serious impacts on human health. A project on 12 different European cities was conducted and conclusions showed that effects of sulfur dioxide and black smoke on mortality were more severe during the

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summer. Health risks involving sulfur dioxide and black smoke are directly influenced or worsened with high temperatures (Patz et al., 2000).

Some regions, such as Los Angeles and Mexico City, are inclined to poor air quality since their local weather patterns are favorable to chemical reactions. This leads to transformation of emissions and restriction of pollutant diffusion (IPCC, 2007). Variations in wind patterns and increased desertification may increase long-distance transport of air pollutants. Under specific conditions, transportation of pollutants such as aerosols, carbon monoxide, desert dust, ozone, and mold spores can arise over a long distance and during four to six days, which can lead to severe health consequences. Origins of such pollutants include both industrial and mobile sources and biomass burning (IPCC, 2007).

Air pollution: can cause respiratory diseases, COPD (chronic obstructive pulmonary

disease), and asthma. • Air pollutants from Forest Fires

Climate change is predicted to cause an increase in fire events in some areas due to changes in temperature and precipitation. Forest fires can cause burns, other injuries, and damage from smoke inhalation. Pollutants originating from forest fires can affect air quality for thousands of kilometers. Particular air pollutants and toxic gaseous are released into the atmosphere leading to acute and chronic illnesses of the respiratory system. This is particularly true for children, and such illnesses include pneumonia, asthma, upper respiratory diseases, and chronic obstructive pulmonary diseases (IPCC, 2007).

In 1997, fires in Indonesia increased the number of admissions in hospitals and the number of deaths from respiratory and cardiovascular diseases (IPCC, 2007). Additionally, loss of vegetation from fires may cause soil erosion and higher risks for landslides (McMichael et al., 2003).

• Toxic chemicals: Can cause cancer. Toxic chemicals are usually associated with health problems such as cancer. On peak

pollution days, summer smog (mostly ozone and acid aerosols) was linked with about half the respiratory admissions. Levels of sulfate have been linked with humidity in the summer and these atmospheric chemicals are consequently very important to understand the relationship between health risks and climate change, including temperature and humidity (Patz et al., 2000).

Health consequences of exposure to both extreme heat and air pollution have been the subject of many recent studies to understand the potential synergistic relationship between both elements. In Athens, Greece there were some interrelations found between high sulfur levels and high temperature (30˚C) (Patz et al., 2000). During the Belgium heat wave of 1994, mortality was found to be linked with the average daily temperature and the 24-h ozone concentration felt during the previous day (Patz et al., 2000). Regulatory agencies use several chemical standards to guarantee human health is not adversely affected. However, with climate change, some of these standards can eventually be modified. There are two ways in which climate change can affect chemical toxins, one direct and one indirect. Direct influence is likely to take place when climate change manipulates the behavior, fate, or toxicity of a chemical. Indirectly, climate change can alter the use patterns of chemicals or types of organisms that are present and

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exposed to toxicity (M. Crane, Whitehouse, Comber, Ellis, & Wilby, 2005). As such, it is important to be aware of such modifications and make a plan. Chemical standards are very important and are used to protect human health and the environment from the undesirable effects of chemical toxicity (M. Crane et al., 2005).

3. Physical/Biological Effects Climate change is likely to affect the seasonality and distribution of serious infectious

diseases (Patz, 2000). Infectious agents vary significantly in type, size, and mode of transmission. Bacteria, protozoa, viruses, and multicellular parasites are examples of infectious agents. These microorganisms evolved with humans as their primary or exclusive host. On the other hand, some non-human species can act as hosts and cause “zoonoses”. There are directly transmitted zoonoses (e.g. rabies) and anthroponoses (e.g. HIV/AIDS) as well as indirectly transmitted vector-borne, anthroponoses, and zoonoses (WHO, 2008). Infectious diseases caused by pathogens are transmitted by insect vectors and are strongly affected by climatic conditions such as temperature, humidity, and rainfall (WHO, 2008). This type of disease includes some of the most significant killers: dengue, malaria, other infectious carried by insects, and diarrhea which is transmitted mostly by infected water (WHO, 2008).

Important determinants of vector-borne disease transmission include the vector’s biting rate, vector’s survival and reproduction, and the pathogen’s incubation rate within the vector organism. Vectors, pathogens and hosts survive and reproduce at optimal climatic conditions which include temperature, precipitation, sea level, wind, and day light duration (WHO, 2008). Infectious diseases demonstrate annual variability. Below is a graph where the relationship between sea surface temperature and cholera case data is demonstrated. The timeframe is from January to December 2004 in Bangladesh (Patz et al., 2000).

Figure 8: Relationship between sea surface temperature and cholera cases in Bangladesh.

Source: Patz et al., 2000.

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Vector borne diseases Vector-borne diseases (VBD) are infectious diseases transmitted by the bite of infected

arthropod species, such as ticks, mosquitoes, and flies. This type of disease is one of the most studied diseases associated with climate change due to its widespread occurrence and sensitivity to climate variability (IPCC, 2007). There is a known relationship between rainfall and vector-borne diseases, such as mosquitoes, which breed in water and consequently depend on water availability. Mosquitoes need access to motionless water to be able to breed and those conditions can be met by both wet and dry weather (McMichael et al., 2003). Heavy precipitation, for example, can both create and destroy breeding sites. Timing and amount of annual rainfall, as well as variation of other climatic factors are determinant factors for breeding conditions (McMichael et al., 2003).

Temperature is very important for vector-borne diseases. Increases in temperature reduce the required time for vectors to breed and decrease the incubation period of the pathogen, which means vectors become infectious at a faster rate. On the other hand, dry and hot weather reduces mosquitoes’ life-period. Higher temperatures also increase the biting behavior of the vector and create smaller adults which usually need more blood meals to reproduce (McMichael et al., 2003).

• Malaria Malaria is one of the major vector-borne diseases, with over 2.5 billion people at risk.

There are around 500 million cases around the world and more than 1 million deaths from malaria every year (McMichael et al., 2003). Malaria is known to be influenced by climate variations. Wet and humid conditions are favorable to the creation of breeding sites and to the increase of malaria mosquitoes’ lives. Temperature also influences the speed at which mosquitoes become adults, determines the frequency at which they look for blood meals, affects their survival capacities, and determines the incubation time of the parasite in the mosquito (Patz et al., 2000). Public health infrastructure, human population growth, travel, immunity, insecticide and drug resistance, land-use change and climate factors are all elements affecting the occurrence of Malaria. High temperatures are fatal to the mosquito and parasite however, at low temperatures, a small rise in temperature can actual increase the risk of transmission (McMichael et al., 2003).

Malaria’s sensitivity to climate can be seen in highland border areas and in deserts where precipitation and temperature play an essential role in transmission of the disease. In these areas higher temperatures and precipitation linked with El Niño can increase the risk of transmission (McMichael et al., 2003). In developing countries, regions of unstable malaria, populations are at risk due to their lack of protective immunity, thus, whenever conditions facilitate transmission these populations are prone to contract diseases (McMichael et al., 2003). In East Africa, data collection from seven highland sites reported that short-term climate variability was more important for the transmission of the disease than long-term trends (IPCC, 2007).

Droughts seem to be very favorable to the transmission of malaria. There are two reasons why drought may contribute to the spread of the disease: (1) drought-related malnutrition reduces human’s immune system making people more vulnerable to infections and (2) droughts can reduce malaria transmission leading to a reduction in

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bacteria immunity in humans. Consequently, in subsequent years there will be an increase in the number of people vulnerable to the disease (McMichael et al., 2003).

A change in ecology of natural predators can also affect vectors’ dynamics. After a dry year, mosquitoes usually recover faster than the predator populations. Many deaths occur after a drought when populations are vulnerable and concentrated in feeding camps and sudden drought-breaking rains increase mosquito abundance. Not surprisingly, many studies have found a positive relation between malaria and extreme events in Africa (McMichael et al., 2003).

Despite known causal links between malaria and climate, there are still many uncertainties (IPCC, 2007). One is because many researchers emphasize the importance of non-climate factors in explaining malaria outbreaks. The occurrence of malaria in Kenya over the last 20 years has been attributed to antimalarial drugs resistance (McMichael et al., 2003). Another study found no relation between climate trends and the timing of malaria occurrence in Kenya (McMichael et al., 2003). Thus, the proposed causes for malaria outbreaks include antimalarial drug resistance and a decrease in vector control activities (IPCC, 2007). Additionally, an increase in international travel has led to more malaria cases in Australia, Europe, and North America (Patz et al., 2000). Seeing this, climate change may increase the risk of malaria except if programs to control vectors are maintained or increased. Areas of concern are those with deteriorated health care systems, such as the republics of former Soviet Union. Actually, these socioeconomic factors are thought to be the cause of recent malaria outbreaks in three Eastern European countries: Turkey, Azerbaijan, and Tajikistan (Patz et al., 2000).

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Figure 9: How Environmental changes affect the outbreak of several infectious diseases

Source: WHO, 2008

• Dengue

Dengue is the most serious arboviral1 disease for humans and occurs in tropical and subtropical regions all over the world (McMichael, 2003). It is expanding rapidly and is transmitted by the Aedes mosquito, a mosquito that breeds in urban environments in artificial containers that hold water (WHO, 2008; McMichael et al., 2003). Cases have increased significantly over the last 40 years since unplanned urbanization with standing water in waste and other locations have produced mosquito breeding sites. The movement of people and goods has also spread mosquitoes and diseases (WHO, 2008).

Many studies have found spatial, temporal, and spatiotemporal associations between dengue and climate. If other determinants remain constant, climate change may be responsible for an additional two billion people exposed to the disease by the 2080s (WHO, 2008). However, the associations between dengue and climate change are not always consistent, showing the complexity of the climate system and disease transmission. Whereas high temperatures and rainfall can lead to a rise in transmission, studies have also shown that drought can increase the cases of outbreaks if household water storage increases the number of mosquito breeding sites (IPCC, 2007).

The disease is believed to have spread because of ineffective vector and disease surveillance, population growth, poor public health infrastructure, unplanned and

1 Arboviral diseases are caused by a group of viruses transmitted by arthropods (an invertebrate animal), such as mosquitoes and ticks (The Free Dictionary, 2010).

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uncontrolled urbanization, and increased travel. It is a seasonal disease associated with warm and humid locations. There are also records showing that increased rainfall can affect transmission potential (McMichael et al., 2003). Roughly one-third of the world’s population lives in areas where the climate is propitious for dengue transmission and outbreaks. Between 250,000 and 500,000 cases of dengue stock-syndrome occurs every year (IPCC, 2007; Patz et al., 2000).

Rodent-borne diseases Rodents act as reservoirs for several diseases whether as transitional infected hosts or

as hosts for arthropod vectors such as ticks (McMichael et al., 2003). There is evidence that diseases transmitted by rodents are associated with heavy rain and flooding due to altered patterns of human-pathogen-rodent contact (IPCC, 2007). Some of the rodent-borne diseases linked to flooding include leptospirosis, tularaemia, and viral haemorrhagic diseases. Other illnesses associated with rodents and ticks are Lyme disease, plague, tick-borne encephalitis (TBE), and Hantavirus pulmonary syndrome (HPS) (McMichael et al., 2003).

The number of rodents has seemed to increase in temperate regions following mild wet winters. One study claimed that human plague cases in New Mexico happened more frequently after winter-spring seasons with above-average precipitation. These conditions usually promote breeding of flea populations and increase food sources for rodents (McMichael et al., 2003). Hantavirus pulmonary syndrome (HPS) appeared first in Central America (Panama) and it occurs mostly from inhalation of airborne particles from rodent excreta (McMichael et al., 2003; IPCC, 2007). The emergence of this disease in the early 1990s in the southern United States was associated with local rodent density. A drought condition at that time reduced the number of rodents. A succeeding intense rainfall increased food availability and that led to a ten-fold increase in the population of deer mice from 1992 to 1993 (IPCC, 2007).

A comprehensive study in the Four Corners Region in the United States, claimed that above-average precipitation levels during the winter and spring of 1992 and 1993 may have contributed to increased rodent populations and consequently to increased contact between rodents, humans, and viral transmission (IPCC, 2007). Climate change can both extend the period of the transmission season and facilitate the spread of tick-borne diseases to high altitudes, like with encephalitis and Lyme disease. The distribution of ticks depends on climatic factors, availability of suitable hosts, predators, and habitat. A study in Sweden associated an increased occurrence of tick-borne encephalitis with extended spring and summer seasons during two consecutive years. Contrarily, in equatorial regions high temperatures can actually decrease tick survival and risk of disease (Patz et al., 2000). Recent studies on plague foci in Asia and North America focused on the relationship among climate, human diseases, and animal reservoirs and suggested that seasonal variations in plague risk can be determined by examining key climatic variables (IPCC, 2007).

Water-borne diseases Water-borne diseases are particularly sensitive to variations in the hydrological cycle

(Patz et al., 2000). They can be classified by route of transmission and distinguished between water-shed diseases (caused by lack of hygiene) and water-borne diseases

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(ingested). There are four things to take into consideration when evaluating health outcomes, changes in rainfall, water availability, and water quality (IPCC, 2007):

• Associations between household access to improved water, water availability, and the health concern brought by diarrheal diseases.

• The significance of extreme rainfall (intense rainfall or drought) in promoting the occurrence of water-borne diseases through drinking water of surface water.

• Consequences of runoff and temperature on chemical and microbiological contamination of coastal, surface, and recreational waters.

• The link between temperature and the occurrence of diarrhea. Access to clean, safe water remains an extremely important global health issue. More

than two billion people live in dry regions and consequently suffer from malnutrition, infant mortality, and diseases linked to contaminated and insufficient water. A small proportion of these diseases can be attributed to weather extremes of climate variability (IPCC, 2007).

Climate extremes can lead to both managerial and physical strains, although well developed water systems should be able to deal with such stresses. Decreased rainfall causes low river flows and decreased sewage runoff or dilution, leading to a rise in pathogen loading. Extreme precipitation, on the other hand, may increase the total microbial population in drinking-water reservoir (IPCC, 2007). Water shortages in developing countries lead to diarrhea illness through poor hygiene and those with low capacity to adapt or with low body defenses are most at risk. In 1995, there were 3.1 million deaths caused by diarrhea diseases and 80% of those were children (Patz et al., 2000).

Floods and droughts are linked to an increased risk of diarrheal diseases. Heavy precipitation can contaminate fresh water from watershed runoff or sewage overflow, while droughts can reduce availability of fresh water leading to a rise in hygiene-related illnesses (Patz et al., 2000; McMichael et al., 2003). The main causes of diarrhea associated with contaminated water supplies are: cholera, giardia, cryptosporidium, shigella, E.coli, typhoid, and viruses such as Hepatitis A. Occurrence of some of these illnesses have been linked to heavy precipitation in countries with regulated public water supply (McMichael et al., 2003).

A zoonotic illness related to domestic livestock called cryptosporidiosis can result from drinking water contamination during times of heavy rainfall. In 1993, an outbreak of this disease in Milwaukee, Wisconsin resulted in 403,000 cases. This outbreak coincided with unusual intense precipitation and melting snow (Patz et al., 2000). A study of water-borne diseases suggested that in the United States half of the outbreaks were linked to heavy rainfall (McMichael et al., 2003).

High temperatures can further increase the risk and intensity of diarrheal diseases through an increase of disease organisms in the environment. In 1997, a significant increase in outbreaks of diarrheal diseases and dehydration in Lima, Peru was associated with above-average temperatures during an El Niño event. At the same location, a time scale analysis linking temperature and diarrhea illnesses suggested that a 1˚C increase in temperature led to an 8% increase of hospital admissions (McMichael et al., 2003). In other words, an above-average temperature of greater than 5˚C led to a greater than 200% increase in diarrhea daily admissions compared to the previous five years (Patz et al., 2000). On the islands of Fiji (1978-1992), the relation was a 1% increase in temperature

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to a 3% increase in diarrhea reports. Intense rainfall was also correlated with the disease (McMichael et al., 2003).

In the marine environment, warmer waters and higher levels of nitrogen are favorable to dinoflagellate blooms, which cause red tides. Red rides can cause paralytic, diarrheic, and amnesiac shellfish poisoning. In Bangladesh, cholera usually follows increased sea surface temperature which develops plankton blooms (Patz et al., 2000). In short, evidence shows that warmer air or water temperature usually leads to an increase in water-borne diseases.

Food Productivity Various factors are important when predicting the impact of climate change on crop

and livestock production. Some direct effects include temperature, CO2 levels, precipitation, sea level rise and extreme climate variability. The indirect effects are climate-induced changes in soil quality, frequency of plant diseases, enhanced food spoilage from humidity and heat, and weed and insect populations (Patz et al., 2000). Several studies found a strong relationship between the occurrence of food poisoning and high temperatures (IPCC, 2007; Patz et al., 2000). During the last two decades, Africa has experienced ongoing deterioration of food production, partly due to droughts (Patz, 2000). The degree to which farmers can respond to such extreme conditions must also be considered (Patz et al., 2000).

Developing countries already fight malnutrition among their large and growing populations and consequently, they are especially vulnerable to any change in food production. Some regions predict that their populations will suffer from hunger due to climate change. One study predicts that by 2060 an additional 40-300 million people (relative to the projected 640 million people) will be at risk from malnutrition due to anthropogenic forces and climate change (Patz et al., 2000). Food contact with pest species like flies, cockroaches, and rodents is also temperature sensitive. In temperate countries, milder winters and warmer weather are likely to boost the number pest species during the summer, since pests will appear earlier in spring (IPCC, 2007).

Warmer sea waters may also lead to altered marine and freshwater ecology, such as increased cases of human shellfish and reef fish poisoning (ciguatera) and the expansion of such diseases. Vibrio parahaemolyticus and Vibrio vulnificus cause non-viral infections associated with shellfish consumption in the United States, Japan, and South East Asia and its profusion depends on coastal water salinity and temperature. A large occurrence of Vibrio parahaemolyticus in 2004 due to the consumption of contaminated oysters was associated with unusual high temperatures in Alaskan waters (IPCC, 2007). Another case where climate change can have a significant impact on food safety is through the methylation of mercury and its following consumption by fish and human beings, as seen in the Faroe Islands (IPCC, 2007).

According to the World Health Organization (WHO), malnutrition and associated diseases are currently the largest contributors to global disease, causing over 3.5 million deaths every year, mainly children in developing countries. Climate change is predicted to increase agricultural production in high-latitude developed countries and decrease agricultural production in several tropical developing regions. The most concerning area is sub-Saharan Africa where people depend significantly on subsistence and rain-fed

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agriculture and have little money to buy imported food. Ten million people are estimated to be at risk of food scarcity and suffer from health consequences from malnutrition (WHO, 2008).

Levels of Aeroallergens Impacts of climate change on human health have received increased attention over the

years. Despite this, impacts of climate change on aeroallergens and associated allergic diseases have been somehow neglected. Some studies found a link between climate change and increased risk of allergic diseases and that climate change is likely to have influence on hay fever (allergic rhinitis) and asthma through its impacts on pollens and other aeroallergens, including house dust mite (HDM), cockroach allergens, and mould spores (Beggs, 2004).

Concentrations of aeroallergens in outdoor air depend on the season and have been linked with several meteorological factors (Patz, 2000). Several studies found increased pollen levels related to increased concentrations of CO2 and/or temperature (Beggs, 2004). In Europe, birch pollen was found more often and in higher concentrations when temperatures were higher and in the U.K, asthma outbreaks were associated with thunderstorms. Therefore, seasonal allergic disorders could be influenced by climate change, although seasonal distribution of asthma is very complex. In temperate climates, asthma is at its highest during the pollen season and later in the year, while in the tropics, asthma increases in wet seasons (Patz et al., 2000).

Figure 10: Summary of the impacts of increased atmospheric CO2 on allergenic plants

Source: Beggs, 2004.

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Some studies have analyzed trends in pollen concentration and distribution over time

and linked them with temperature. Recent studies found that rising concentrations of pollen over the past decades in the twentieth century were related to climate change (Beggs, 2004). Another hazard for human health is the introduction of new invasive plant species with high levels of allergenic pollen. Ragweed (Ambrosia artemisůfolia) specifically is spreading in several parts of the world and poses several health risks to humans. There are several studies linking an increase in CO2 levels and temperature with a rise in ragweed pollen production and the extension of ragweed pollen season (IPCC, 2007). Warmer temperatures and higher concentrations of CO2 in urban areas led to higher levels of ragweed production when compared to rural areas. Some studies have also looked at the relationship between climate change and the allergenicity of pollen and at higher temperatures, trees produced significantly stronger allergenicity (Beggs, 2004).

According to IPCC’s Fourth Assessment Report, climate change has led to an earlier spring pollen season in the northern hemisphere (IPCC, 2007). A study in Europe found trends towards earlier season start dates of about six days over the next ten years, if the this trend continues. Additionally, two other studies found a link between earlier pollen seasons with a warming period in Italy from 1891 to 2000 (Beggs, 2004).

In a meeting by the World Health Organization, it was concluded that “an earlier start and peak of the pollen season is more pronounced in species that start flowering earlier in the year” and that “duration of the season is extended in some summer and late flowering” (Beggs, 2004). Lastly, higher concentrations of CO2 levels and warmer temperatures typically from urban areas led to earlier flowering of ragweed in urban areas than in rural areas (Beggs, 2004). It is rational to say that aeroallergen diseases have experienced a change in seasonality. Nevertheless, according to IPCC latest assessment report there is still limited information to confirm that the length of the pollen season has increased in time (IPCC, 2007).

The relationship between distributions of allergenic plants and pollen has been considered since climate change and human health have first been examined. Climate change is likely to extend distributions of such plants and pollen, thus increasing the risk for human health. Increased pollen production, linked to increased levels of CO2 could be even more serious with wind pollination. Pollen distribution is influenced by atmospheric elements such as wind speed and direction, humidity, rainfall, and so on (Beggs, 2004).

Lastly, most studies done on aeroallergens focused on pollen and mold spores and very little work was done on other types of aeroallergens. However, one of the few studies analyzing other types of aeroallergens suggested that in temperate regions, an increase in temperature resulting from climate change will facilitate the spreading of cockroaches from domestic areas to sewers, which will make the control of infestations more difficult to execute (Beggs, 2004).

4. Sociodemographic Effects Climate change will have sociodemographic effects that include forced displacement,

overcrowded living, and human conflicts (wars) (Patz et al., 2000). Forced migration can be a result of sea level rise and hydrological cycle disturbances that result in repeated flooding, especially of coastal communities and shortage of food and water. These refugees are called eco- or environmental refugees and this is a new phenomenon in the

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world. In 1995, there were at least 25 million environmental refugees, compared to 27 million traditional refugees (people seeking relief from political oppression, religious prosecution and ethnic conflicts) (Myers, 2002). Climate change aggravates this situation. There could be up to 200 million people impacted by sea-level rise, coastal flooding, and severe droughts (Myers, 2002). Twenty of the thirteen largest cities in the world are at risk of suffering from flooding because they are situated at or below sea level (Patz et al., 2000). Rising waters can also lead to salinisation of coastal freshwater aquifers and disturb storm water drainage and sewage disposal (Patz et al., 2000). In Texas, sea level rise and severe storms are a serious problem aggravated by climate change and consequently that can lead to more eco-refugees in the state.

Unequal access to resources, such as food and water supplies and the degradation of the environment can lead to violent behavior and conflict among affected groups (Patz et al., 2000; Reuveny, 2007). Forced migration can also lead to different ethnic groups living together, which can create tension and mistrust among different groups (Reuveny, 2007). Competition may occur over jobs, land, and resources (Reuveny, 2007). In Texas, some of the forced migration can also come from Mexico, as people travel to the United States seeking relief from food and water shortages.

Outdoor occupational health will also see changes due to potential heat stress, heatstroke, and increased humidity. Solar ultraviolet radiation (UVR) contact can be detrimental and dangerous to human health. Worldwide, excessive exposure to UVR has caused the loss of approximately 1.5 million disability-adjusted life years and 60,000 early deaths in 2000. The major illnesses caused by UVR are cutaneous malignant melanoma, sunburn, and cortical cataracts (IPCC, 2007).

Populations will have to adjust their clothing to climate change, as well as the amount of time spent on outdoor activities. The only positive thing about UVR exposure is that ultraviolet B frequency band is essential for the body’s production of vitamin D. Sun exposure deficiencies may cause osteomalacia (rickets) and other illnesses caused by lack of vitamin D. Seeing this, although sometimes neglected, risk assessments need to include these sociodemographic effects to obtain a more comprehensive understanding of how climate change may impact human health (IPCC, 2007). Table 3 summarizes the health impacts of climate change described previously.

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Table 3: Anticipated Human Health Impacts of Global Climate Changea Health impact

category Mediating process Health outcomes Examples of specific

diseases or injuriesb

Physical effects Increased number of extremely hot days, decreased number of

extremely cold days, urban heat island effect.

Extreme weather events Flood, severe storms

Drought

Altered incidence of heat and cold stress.

Exposure to trauma, loss of

shelter.

Famine.

Exposure to wildfires, respiratory effects of

inhaled smoke.

Heat stroke, cardiovascular failure

Traumatic deaths and

injuries, drowning, PTSD.

Malnutrition, impairment of child growth and

development. Burns, PTSD, COPD,

asthma. Physical/chemical

effects Weather effects on air

pollutant formation and transport, flooding and

release of toxic chemicals from disposal sites.

Respiratory diseases. Diseases related to heavy

metals or toxic waste.

COPD, asthma Cancer

Physical/biological effects

Weather effects on disease agents, vectors or their

habitats.

Altered marine and freshwater ecology,

microbial contamination during flooding.

Altered food productivity, nutrient value, and plant

pathogens. Effect on levels of

aeroallergens (pollen spores, etc).

Altered incidence and geographic distribution of

vector-borne diseases.

Altered incidence of water-borne and food-borne

diseases.

Impaired access to food supplies.

Respiratory diseases,

allergic disorders.

Malaria, dengue fever, encephalitis, hantavirus

infection, Rift Valley fever, Ross River virus infection.

Cholera, Cyclospora infection,

cryptosporidiosis, Campylobacter infection, food poisoning, shellfish poisoning, leptospirosis.

Malnutrition, impairment

of child growth and development.

Asthma, allergic rhinitis.

Sociodemographic effects

Forced migration, overcrowded living

conditions, human conflicts 9wars).

Infectious diseases, nutritional impairment, mental health problems,

exposure to trauma.

Diarrheal diseases, malnutrition, impairment

of child growth and development, depression,

PTSD. Source: Patz et al., 2000 aTemperature rise of 2˚C by the year 2100, sea-level rise of 49cm by the year 2100, and an increase in hydrologic extremes. bPTSD, Post-traumatic stress disorder; COPD, chronic obstructive pulmonary disease.

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Given the wide range of impacts climate change can have (table 3), health professionals will have to respond effectively. Preparedness measures will depend on the population’s level of vulnerability to climate change. In the long run, governors need to consider health care workforce, so populations are able to respond to the expected health impacts brought by climate change, and plan long term adaptive health policies (Blashki, McMichael, & Karoly, 2007). Some of the primary health care adaptation measures according to Blashki et al. (2007) include:

• Public awareness and education • Alert Systems: including imminent severe weather events and infectious

diseases. • Better infectious diseases control programs- vaccine problems, vector control

and food safety. • Improved surveillance of health risk causes and health outcomes. • Proper health workforce training.

III. Climate Change and Human Health in Texas

Texans live daily with two significant problems: severe air pollution and water scarcity (Musil, 2003). Intense air pollution seen in large cities like Houston and Dallas-Fort Worth is already causing several deaths each year (Barrows, 2003). Texas already faces a natural precipitation gradient, moving from the wet eastern part of the state to the drier west. Precipitation predictions as a result of climate change suggest that the disparity could get greater.

1. Texas Air pollution, Human Health, and Climate Change Currently, eight percent of Texans live in urban areas where ground-level ozone is a

serious health problem. Between 1998 and 2000, 16 of the 22 reporting counties in the state had an “F” from the American Lung Association for the number of days with higher than acceptable ozone levels according to EPA limits (Barrows, 2003). Texas runs 19 coal-burning plants and is very dependent on coal for its energy supplies (Figure 11). These plants represent one of the most polluting amenities in the world, emitting sulfur dioxide, mercury, CO2, and nitrogen dioxide into the air. Texas and Louisiana together host 50% of the refinery “hot spots” in the country (Barrows, 2003).

In Texas, chronic respiratory illnesses, such as asthma, have been increasing in both adults and children. In 1998, a year of extremely high temperatures and ozone levels, 343 people died from asthma and $435 and $328 million was spent on direct and indirect medical expenses respectively (Barrows, 2003).

Most air pollution comes from energy production, mainly from fossil fuel burning. As seen in figure 11, Texas relies heavily, almost 96%, on natural gas, coal, and nuclear power for its electricity. More than half of its coal and nuclear power is imported and more than one-third of its electricity comes from coal (Barrows, 2003).

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Figure 11: Texas Electricity Generation by Energy Source, 2007

Source: EIA, 2009.

Natural Gas, 49.2%

Coal, 36.3%

Nuclear10.1%

Other Renewables,

2.5%

Other Gases, 0.9%

Hydroelectric 0.4%

Petroleum, 0.3%

Other, 0.2%

2. Water supply, water quality and Climate Change in Texas Texas’ vitality remains in the continuous availability of water. However, the state is

decreasing its water resources at a significantly fast pace. Climate change is predicted to reduce rainfall in the winter in Texas and increase it approximately 10% in other seasons. The state’s main groundwater sources are already being overspent and El Paso’s aquifer may be exhausted by 2030 (Barrows, 2003).

Texas is the second most populated state in the nation and its population is expected to double to about 35 million by 2040; assuming the scenario 0.5 (Texas State Data Center and Office of the State Demographer, 2010). Municipal and industrial water demand will consequently increase for the next decades and as such, Texas needs an effective plan to have adequate water supplies for the next 50 years (Barrows, 2003).

There has been at least one area in Texas that has suffered from a drought in every decade of the 20th century. For example, a severe drought during the first half of the 1950s caused an estimated 65% decline in runoff statewide and over 60% decrease in flows to the coast (Barrows, 2003).

Recently, drought in Texas has reached its most extreme since the last 50 years. A combination of high temperatures and low rainfall led to a $3.6 billion crop and livestock losses in 2009 (Benning, 2009).

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Figure 12: U.S. Drought Monitor: Texas, September 22, 2009

Source: Barrows, 2003. Climate change is expected to further decrease precipitation by 5% over the next 50

years and increase temperature by 2ºC (Harte Research Institute & Texas Parks and Wildlife, 2010). This will aggravate the intensity and frequency of droughts, the access to freshwater, and the consumption of electricity to respond to the increased temperatures. Texas water resources are already limited and climate change will make them even scarcer.

There are two types of water sources in Texas: surface water and groundwater. With no winter snow or moderate-intensity rainfalls as a water source, thunderstorms are the main source of surface water. Consequently, man-made reservoirs are of extreme importance to Texas since they supply almost all surface water used for consumption. Hydrologically, the state is very diverse and can be divided in four different parts (Barrows, 2003):

• High Plains- with only 7% of the population, it accounts for 70% of groundwater withdrawal, mostly for agriculture.

• East Texas- with approximately the same population as the High Plains, it’s the most water rich area of the state. It serves most metropolitan areas of the state, such as Houston and Dallas. Nevertheless, six years of severe drought influenced by climate change is predicted to decrease Dallas reservoir levels to about 22% of conservation capacity.

• Central Texas- contains the majority of the population and the major industrial areas of the state. San Antonio’s water supply comes from Edwards’s aquifer in south-central Texas.

• South Texas- this is the most arid region of the state. Already prone to droughts, this area depends mostly on agriculture, which demands more than 85% of the available water in the area. With higher birthrates and steadily increasing immigration, municipal water demand is predicted to double or triple by 2040. Economists estimate that this water deficit in the Lower Rio

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Grande Valley alone has an impact of $400 million on agriculture. Although water demand for irrigation is declining, municipal and industrial demand is predicted to increase significantly. Population in this region grew 22.8% from 1990 to 2000 and this will make it more difficult to handle Texas’ threatened water supply.

Droughts and floods can lead to contaminated water causing water-borne diseases. Low stream flows and decreased water supply derived from droughts make water prone to contamination since salt and toxins tend to concentrate. Increased salinity is a major concern in some areas of Texas such as the Lower Rio Grande Valley. In the Falcon reservoir, the area’s main water supplier, salt concentration is twice as much as those in drinking water supplies throughout the country (Barrows, 2003).

Water for agricultural purposes is also endangered. Seventy percent of irrigation’s water is groundwater, in which high levels of nitrates are seen throughout the whole state. In 2000, more than 7,500 cases of groundwater contamination were reported statewide, mostly due to leaking petroleum storage tanks. Lastly, around 10% of Texans depend on private groundwater settlements, of which a great number surpass drinking water standards for nitrates and arsenic (Barrows, 2003).

3. Climate Change Impacts in Texas According to Barrows (2003), in Texas, impacts of climate change will be felt in a

number of ways: More frequent and severe attacks of asthma, an increased occurrence of strokes, and aggravation of other respiratory illnesses and cardiac problems resulting from:

• Increased emissions of carbon dioxide, nitrogen oxide, sulfur dioxide, particulate matter and other toxic pollutants

• Increased ozone (smog) levels • Increased pollen levels • Increased dust particulates

Changes in quality and supply of freshwater due to: • Warmer temperatures resulting in increased evaporation and changes in

precipitation, which can further endanger water resources • Higher risk of disease from bacterial, parasitic, and viral infections caused by

consumption of water contaminated by animal and human waste • Weakened water quality caused by drought and floods

More accidents and injuries caused by severe weather events • More severe and frequent tropical storms causing an increase in mortality and

morbidity, mostly along the Gulf Coast • A rise in heavy rainfall leading to more flooding

Higher health risk for vulnerable populations: • Poor border populations live with a higher health risk, mostly for mosquito-borne

diseases, intestinal infections, and respiratory diseases • There is a higher risk of respiratory problems such as asthma, especially among

children • Elderly and poor are among those with higher risk of heat-related illnesses

Higher risk of infectious diseases:

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• Greater risk of mosquito-borne diseases such as dengue, malaria, and West Nile Virus

Increased number of heat-related illnesses: • Number of deaths caused by heat stress could increase significantly • Children, elderly, and the poor are those with higher risk of heat-related mortality

Warmer temperatures and more frequent heat waves may lead to increased heat-related mortality and illnesses in Texas. The state, with its already intense heat waves may be especially vulnerable to this situation. One study projects that in Dallas by 2050, heat-related deaths could increase from around 35 to 100 summer heat-related deaths (however, air-conditioning may not have been properly taken into consideration in this projection). Warmer temperatures could also lead to a decrease in winter mortality, but winter-related deaths are thought to change very little in Texas (EPA, 1999).

Extreme Heat and Texans’ Health It is believed that heat-related deaths usually occur early in the summer in places

where it is normal to see extreme heat. Although Texas is already characterized by extreme heat during the summer, climate change can make the state even more vulnerable to heat stress and increased temperatures. There has been a warming trend in Texas since the late 1960s. Between September 1-5, 2000, Texans experienced the hottest days in the state’s history with more than 15 local record-highs broken. As seen on the table below, in four out of ten years Texas ranked first as the state with the most heat-related mortalities. Additionally, in 26 cities with more than 25 four-day heat waves in the 1990s, eight were in Texas (Houston, Brownsville, Midland, El Paso, Corpus Christi, Austin, Fort Worth, and San Antonio) (Barrows, 2003).

Table 4: Heat-related Deaths in Texas, 1998-2005 (* indicates #1 ranking).

Year Texas Heat-related Deaths Total U.S. Heat-related Deaths 2005 49 158 2004* 03 06 2003 0 36 2002 1 167 2001 20 166 2000* 71 158 1999 22 502 1998* 66 173 1997 2 81 1996* 10 36

Source: Adapted from Barrows (2003) and compiled from National Weather Service data, “Heat-related fatalities,” “http://www.ncdc.noaa.gov/oa/climate/sd/.”

One study predicts that by 2050, heat-related deaths during a typical summer could

increase three times more, from approximately 35 to over 100 deaths (Musil, 2003). Urban residents are at higher risk of suffering from heat stress since buildings absorb heat during the day and release it during the night, called the “heat island effect.” Cities such as Houston, for example, are usually 5 to 9˚F warmer than nearby areas (Barrows, 2003).

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Climate change is increasing breeding grounds and livable areas for mosquitoes that carry diseases. Warmer temperatures favor faster maturation and development of mosquitoes and insect-borne diseases, such as West Nile Virus and dengue, have now emerged in Texas (Barrows, 2003). West Nile virus first appeared in Texas in 2002 and by the end of that year, 202 cases were reported, of which 13 resulted in death. Between1980 and 1999, more than 62,514 cases of dengue were reported in Mexican states bordering Texas, while 64 were reported in Texas. The disease represents a major threat to the public, especially in South Texas. In 1999, Dengue sickened over 51 people in Texas, 16 of which caught it in South Texas. One death resulted from those outbreaks, the first one in Texas in decades (Barrows, 2003).

Extreme Weather Events and Texas Extreme weather events are not unusual for Texans. Historically, hurricanes have hit

Texas once every five years. High density coastal development makes this state prone to devastating damage when hurricanes strike. Extreme weather events in Texas causing damages of more than $1 billion occurred over 16 times between 1998 and 2001. Texas is one of two states in the country sharing this characteristic (Louisiana is the other) (Barrows, 2003). Climate change is expected to increase the frequency and intensity of extreme weather events, so the impacts of hurricanes may be aggravated during the next years (IPCC, 2007).

Vulnerable People and Regions in Texas A study by Longstreth (1999) about possible public health consequences due to

climate change by U.S. region found that some regions may suffer disproportionately when compared to others. Figure 13 illustrates the geographic distribution of weather-related health impacts. Figure 14 depicts the weather-related health consequences in Texas.

Figure 13: Geographic Distribution in the United States of Weather-Related Health Effects.

Source: Longstreth, 1999

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Figure 14: Texas Weather-Related Health Effects.

One or more cases of Hantavirus infection

Ten or more cases of imported cases of malaria in 1994 or multiple cases of Dengue

Current of past history of algal blooms or food poisoning from fish/shellfish.

Recent experiences with health impacts from storms/floods.

Current of past history of arbovirus encephalitis

One or several ozone nonattainment areas Source: Adapted from Longstreth, 1999.

Some populations are more vulnerable than others to climate change. In Texas, the

most vulnerable are Hispanics, which represent almost a third of the state’s total population (Barrows, 2003; Longstreth, 1999). Hispanics in the state have excessively higher exposure to outdoor and indoor pollutants, pesticides, hazardous waste sites, lead, and mercury. This makes them more vulnerable to morbidity, premature death from asthma, behavioral and developmental problems, lead poisoning, and cancer. This is mostly due to environmental stressors and exposures that are aggravated by climate change (Barrows, 2003). Additionally, lower income levels, place of residence, and occupation make them more vulnerable to toxins and disease than any other population (Barrows, 2003; Longstreth, 1999). Demographically, climate change is proven to have higher impacts on the elderly, children, poor, those with low immune system defenses, those with heart diseases, those below poverty line, those without health insurance, and those receiving Medicaid and Medicare support (Barrows, 2003; Longstreth, 1999; Patz et al., 2003; IPCC, 2007).

Children under five years of age represent 8.3% of Texas population, more than the national average of 6.9%. This sector of the population is especially vulnerable because they are still developing (Barrows, 2003; U.S. Census Bureau, 2009). The elderly, those with 65 years-old or older, represent 10.2% of the Texas population versus 12.8% as the national average (U.S. Census Bureau, 2009). This group shares similar health risks as children, with the exception that they start losing functions. The poor, that is, people living below the poverty line represent 15.8% of the Texas population, compared to

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13.2% in the country (U.S. Census Bureau, 2010). In 2000, there were 4.4 million people in Texas under 65 years of age without health insurance, which is 23.6% of the total population. Since 1998, Texas has had the highest percentage of people without health care coverage in the country and one-third of the Texas-Mexico border population does not have insurance (Barrows, 2003). Texas-Mexico Border Region

The poorest regions in the world are the most vulnerable to the impacts of climate change. Texas has approximately 1,500 areas which lack basic water and sewer systems, paved roads, and sanitary and safe housing. These conditions make its population extremely vulnerable to climate variability. During the last few decades, regions near the border have seen a great development and industrial growth. Two reasons for this are the Border Industrial Program (1965) and the North American Free Trade Agreement (1992), which promoted trade between the U.S. and Mexico and led to explosive population growth. New factories along the border have grown by about 50% since 1993, leading to an increased congestion and higher population density. This has limited the region's ability to provide clean water, sanitation, and other services. Twelve percent of the border population does not have access to clean water and 30% does not see wastewater treatment. Consequently, populations in these regions, especially children, face serious health risks (Barrows, 2003).

Air quality is another major concern for these border regions. Increased industrial emissions from factories and higher traffic volume represent a serious threat for Texans’ health. Additionally, less rigid environmental laws in Mexico than in the U.S., for both power plants and vehicles, represent a health hazard for people on both sides of the border. Higher temperatures and climate change will further aggravate the health risks already seen in border regions (Barrows, 2003).

The Texas Coastline

The coastline is the site of Texas’ main industrial and urban areas. Over half of the country’s chemical and petroleum production is situated along the Texas coast. These facilities are threatened by sea-level rise and tropical storms and have to withstand the costs of the consequent damages from such occurrences. Thus, the Gulf Coast is one of the most vulnerable areas to climate change in the state (Barrows, 2003). The impacts of Ivan in 2004, the impacts of hurricanes Rita, Katrina, and Wilma in 2005, and the impacts of hurricane Ike in 2008 showed that offshore oil and natural gas platforms, pipelines, petroleum refineries, and supporting infrastructure can be seriously damaged when an hurricane hits. Hurricane damages can cause national-level impacts and its consequences can last for months or more (IPCC, 2007).

Another concern for the Texas Gulf Coast is any change that affects the sea, whether it is water temperature, wind, currents, nutrient levels, or precipitation patterns. One major health concern is food-borne disease transmitted by fish and shellfish in contaminated waters. Warmer seas influence the intensity, duration, and extent of dangerous algal blooms (Barrows, 2003) and in Texas, one of the most dangerous species is Karenia brevis (formerly Gymnodinium breve) (Barrows, 2003; Texas Parks and Wildlife, 2009). Most recently, harmful algal blooms have occurred in the Texas coast during the fall of 200 and 2005, the summer and fall of 2006, beginning of 2007, and fall

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of 2009. In the fall of 2000, harmful algal bloom covered 300 miles of Texas coastline and closed oyster beds for weeks to prevent human poisoning from shellfish (Barrows, 2003). It caused a minimum direct impact on Galveston County of $9.93 million, and a maximum direct economic impact of $11.5 million, showing that these extreme natural events can have significant economic effects (Evans & Jones, 2001).

As said previously, given the wide range of impacts climate change can have in Texas, health professionals will have to respond effectively. Health workforce and adaptive health policies need to be taken into consideration by policy makers. Public awareness and education, early alert systems, proper disease control programs, improved surveillance, and quality health workforce training are important primary health care adaptation measures (Blashki et al., 2007). Additionally, the threat of sea level rise and more frequent and severe weather events in South Texas may make it more difficult to retain and recruit health professionals such as nurses and physicians. This can result in a shortage of health care services and an increase in health care costs and both would drive the cost of inaction to even higher levels (Benavides, personal communication, 2010).

IV. Mitigating Climate Change: Costs and Benefits

1. Costs of Inaction Climate change and its consequences on human health will have, and is already

having, serious economic impacts. More frequent and severe weather extremes and more frequently transmitted infectious diseases will increase mortality, morbidity, and injuries. Consequently, more money will be spent on human health. From 1980 to 2004, the economic costs of weather-related natural disasters worldwide were $1.4 trillion (in 2004 US dollars) (Anderson et al., 2005).

Table 5 illustrates some of the impacts of climate change on human health worldwide and the dollar amounts spent as a consequence.

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Table 5: Economic Impacts of Climate Change Effects on Human Health. Cost of

treatment/damage Costs (continued) Observations

Malaria An average of $6 per person for treatment in

Mozambique.

West Nile Virus $500 million spent in 1999 in the USA on the

disease.

Lyme Disease $60,000 per case/treatment.

National expenditure of US$2.5 billion over 5

years for the therapeutic interventions.

Allergic Diseases:

• Asthma

• Allergenic rhinitis

There are approximately 37 billion lost-days of

work and school due to allergenic diseases.

Costs increased from $4.5 billion (mid-1980s) to over $10 billion (mid-

1990s).

Total direct and indirect costs rose from $2.7

billion in the 1990s to $4.5 billion this decade.

US $2.42 billion in 2003 in the US (underestimate since values are adjusted

from 1991 and cases increased).

Annual direct and indirect costs for asthma rose from $6.2 billion in

the 1990s to $14.5 billion in 2000.

Heat Waves Cost includes life insurance payments, wildfire deaths, property damage and direct health costs.

Livestock and crop losses were around US $12.3 billion. Fire and timber losses in Portugal were US $1.6 billion.

Cost of monitoring and preparing for heat waves in subsequent years was around US $500 million annually.

Flooding In England, the current annual figure of US$2.4 billion of annual losses could reach $48 billion in the coming decades.

In 2002 a serious flood resulted in US$3 billion in the Czech republic and over $9 billion in Germany. In France in 2003 economic losses were US$1.5 billion.

Consequences include the event itself, recovery period, risk/anxiety of recurrence.

Forest In the summer and fall of 2003 wildfires cost more than US $3 billion in the USA. .

In British Columbia, enough trees were infested and killed to build 3.3 million homes or supply the entire US house market for two years.

Source: Adapted from (Anderson et al., 2005).

2. Costs of Climate Mitigation According to a report by the House of Lords in 2007, climate change and the severity

of its impacts will continue to rise unless emission of GHGs is reduced or stabilized.

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Strong action is needed to delay, stop, or overturn the continuous rise of GHGs emissions. Stabilization means reducing annual emissions to levels that balance the Earth’s natural capacity to remove greenhouse gases from the atmosphere. In the long run, emissions will have to be reduced below 80% of current levels to reach stabilization. The longer before actions are taken, the more drastic the cuts will have to be. Stabilizing at or below 550 ppm of CO2 would require global emissions to peak in the next 10-20 years and then fall at a rate of at least 1-3% annually. By 2050, global emissions would have to be 25% lower than current emissions (Stern, 2007). Key costs of mitigating climate change include private costs, which are those facing individual decision-makers based on market prices, and social costs, which are private costs plus costs of externalities (opportunity costs are taken into consideration). Estimating costs is a very complex process that includes factors such as discounting, treatment of externalities, market efficiency assumptions, valuation issues, and techniques linked to climate change damages as well as implementation and transaction costs (IPCC, 2007).

Integrated Assessment Models (IAMS) combine simplified climate models and economic models of the world economy to produce estimates of costs. As the target for reducing CO2 emissions becomes tougher, so do the costs of meeting such goals and its related incremental costs (IPCC, 2007). The speed of reducing emissions required to reach a stabilization goal depends on both timing of the emissions peak and its height. Postponing action now means more drastic emission cuts over the next few decades (Stern, 2007). There are several possible emission trajectories with early or late peaks and more gradual or drastic cuts. Figure 15 illustrates seven possible paths to stabilization at 550 ppm CO2e.

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Figure 15: Illustrative paths to Stabilize at 550ppm CO2e*

Source: Stern, 2007

*Generated with the SiMCap EQW model. Although all trajectories are possible, those with late peak emissions make the world

more vulnerable to unexpected changes in the Earth’s climate system. Late emission reductions hold higher risks in terms of climate impacts: if emissions are accumulated faster, temperatures will also increase faster (Stern, 2007). Another problem with late peaks and rapid reductions is that they are usually not economically viable. Higher cuts have been historically associated with economic recession or turmoil. Seeing this, it would be beneficial for Texas to start stabilizing GHG emissions since later actions are more risky and less economically viable. Lastly, stabilization at 550 ppm CO2e or below is considered achievable and consistent with economic growth (Stern, 2007). Figure 16 shows emission trajectories for 450-550 CO2e and business as usual (BAU).

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Figure 16: BAU emissions and stabilization pathways for 450-550 ppm CO2e.

Source: Stern, 2007.

As expected, different scenarios bring different costs. The IPCC Synthesis Report in

2001 tried to estimate how much reducing greenhouse gases emissions would cost, based on Integrated Assessment Models and atmospheric concentrations (IPCC, 2007). The figure below illustrates the costs of achieving a 550 ppm target. Table 6: Annual Costs to the World of achieving the 550ppm target, $2005 prices. Present Value of cost $2005 prices, trillion.

Annual cost at 3%, borne in first 50 years, billion.

Annual cost at 3%, borne in first 20 years, billion

2 78 134 17 661 1141

Source: House of Lords, 2005.

Achieving the target is equivalent to spending $2 to $17 trillion at once today. As an annual flow it would be close to $78 to $661 billion annually. At the time the report was done, the world’s annual Gross Domestic Product (GDP) was about $35 trillion, so annual expenditures would be 0.2% to 3.2% of annual world income (House of Lords, 2005).

Another way of expressing the costs of achieving lower emissions is cost per ton of carbon reduced (tC). The table below illustrates that analysis. Results show that the cost per ton of carbon to achieve the 550ppm target is between $18 and $44tC.

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Table 7: World Costs per Ton of Carbon. Concentration target (ppm)

Cumulative emissions, billion tC

Incremental reduction in emissions billion tC

Incremental cost at 3% discount rate $2005, trillion

Incremental cost per tC $2005.

MERGE FUND MERGE FUND 750 1348 - 0.7 0.0 - - 650 1239 109 2.0 8.7 18.3 79.8 550 1043 196 3.5 8.7 18.3 44.4450 714 329 4.3 19.5 13.1 59.3 Source: House of Lords, 2005.

Although discussing only the costs, reducing emissions and mitigating climate change will reduce mortalities and illnesses, improve human health and environmental conditions, and reduce the economic impacts associated with human lives and environmental livelihoods. The benefits of taking action to mitigate climate change will be discussed next.

3. Benefits of Climate Mitigation Stopping the course of climate change would result in benefits for human health

directly related to decreases in temperature and associated impacts. Climate policies aimed at reducing GHG emissions would also improve air quality and other ancillary health benefits. Whereas the benefits from climate mitigation through climate policies would be felt over the long-run, the ancillary health benefits would be felt in the short-term (Bell et al., 2008).

Ancillary benefits are side benefits of mitigating problems such as air pollution, which brings consequences on employment, land quality, and improved health. Sometimes they can be called ancillary impacts, meaning they can either be positive or negative. Most of the ancillary benefits reviewed focused on human health, the most significantly quantified impact of all (IPCC, 2001).

To make the comparison of policies easier, outcomes are usually converted into comparable formats. One method is to convert health outcomes into economic terms that allow direct comparison between costs and benefits.

One way of estimating economic costs or benefits is by attributing a value for saved lives (VSL). There is a global economic value of loss of life due to climate change that ranges between $6 billion and $88 billion (1990 dollar prices) (IPCC, 2001). These prices help estimate the costs and benefits of climate change impacts on human health. The cost of mortality is estimated to be higher in low-income countries, where, ironically, economists attribute a lower value to life. Some suggest attributing a global average value instead of a national value to life and that this change would increase mortality cost by as much as five times (IPCC, 2001). The table below is a sample of values used for premature mortality-related health impacts.

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Table 8: Sample of typically used values for Premature Mortality-related impacts (mean estimates) ($2000 PPP-adjusted).

Health Effects US EU Canada Australia New

Zealand Mortality: 1,042 1,296,552

(premature death)

VSL: Adults

6,300,000 2,247,191 3,480,000 1,439,394 1,717,241

VSL: Children

2 x adult 4088764 (infant) 134,831

70,455

118,621

Morbidity:

1929.55 (average cost/separation)

Morbidity Children

2 x adults

Chronic Bronchitis

340,000 213,483

Chronic Asthma

39,000

Respiratory hospital admission

14,000 2,247 1,032 2,069

CVD Hospital admission

21,000 2,247 1052 2,759

Emergency room visit

300 (asthma) 541 (respiratory) 562 (CVD)

Doctor’s Visit

60

Rheumatoid Arthritis Disease

106 92 (working age) 78 (young, elderly)

22 53

Asthma Day

32-74 43 15

Source: Bell et al., 2008. Note: * VSL derived from population weighted values in the Australian Bureau of Transport and Regional Economics (BTRE) assessment.

According to a study by the WHO/WRI/EPA Working Group on Public Health and Fossil Fuel Combustion, reducing CO2 emissions would prevent 700,000 premature deaths by 2020 (World Resources Institute, 1997; IPCC, 2001). Adopting climate policies now can bring benefits locally and globally by decreasing particulate air pollution and protecting human health. Over the next two decades at least 8 million deaths could be avoided with climate policies worldwide. This includes approximately 563,000 deaths

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each year in developing countries and 140,000 in developed countries (World Resources Institute, 1997). Figure 17 illustrates the potential saved lives from climate policies.

Figure 17: Lives potentially saved annually from climate policies

Source: Davis, 1997.

In developed countries, air pollution is among the top ten causes of death (Davis,

1997). A study by Davis (1997) showed that in the United States, the potential number of lives saved annually by reducing air pollutants is equal to the number of deaths from HIV or infectious liver diseases in 2000. The study used a conservative approach since it took into account only adults over 30-years old and infants less than one year old. It did not account for deaths due to other pollutants and less dramatic events such as avoided illnesses and days lost from work (World Resources Institute, 1997). According to two different studies, the average ancillary benefits of reducing CO2 emissions in the U.S. are US$41/tC in 1996 dollars or $56.26/tC in 2008 dollars (IPPC, 2001). Consequently, numerous measures are being addressed by several entities and countries to adapt to climate change. Balancing actions that decrease vulnerabilities and facilitate climate stabilization is a standard that can guide public policy, private investment, and insurance policies (Anderson et al., 2005).

During July 6-14, 1993 in Philadelphia, Pennsylvania, 117 people died due to heat stress. Partially in response to these heat waves in Philadelphia, in 1995 a weather system was developed to protect the city’s population when weather conditions created health risks. The system was called Philadelphia Hot Weather-Health Watch/Warning System (PWWS) and identified major airmasses in Philadelphia for the current day and the two following days. Analysis then determined which airmasses were related with excess mortality during the summer season. After the analysis was made and reported, the Philadelphia Department of Health implemented emergency safety and mitigation measures to decrease mortality risk (Ebi, Teisberg, Kalkstein, Robinson, & Weiher, 2004a). The results of this system were saving of around 2.6 lives per day or 117 lives over a three-year period. Using a value of a statistical life (VSL) of $4 million for people 65 years of age or older (EPA’s estimate and Krupnick et al., 2000 assumption that VSL falls with age), the gross benefit of using this warning system was $468 million. The costs of implementing and maintaining the system running were approximately $210,000

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over the three-year period, almost irrelevant when compared with the gross benefits. The net benefits of using PWWS were $467.79 million and 117 lives saved over the three-year period (Table 9; (Kristie L. Ebi et al., 2006; Kristie L. Ebi et al., 2004). Table 9: Benefits of Using Philadelphia Hot Weather-Health Watch/Warning System (PWWS). Over the 3-year period Per-Day

Lives Saved 117 2.6

Gross Benefits $468 million $10.4 million Costs $210,000

Net benefits $467.79 million Source: Adapted from Ebi et al., 2004.

Seeing that in 2005 Texas had 49 heat-related deaths and assuming that by using such system those deaths could be avoided, the gross benefits for Texas could have been $196 million in 2005 alone (Angel, Hinson, & MacAloney, 2005). A study by Environmental Texas and led by Applied Climatologists, Inc., predicted that heat-related deaths in cities like Houston will increase from approximately 24 to nearly 32 per year, leading to additional 192 heat-related deaths by 2050, with increased summer temperatures driven by climate change. An analysis of 21 U.S. cities found that 23,160 additional deaths can occur with increased temperatures induced by climate change (L. S. Kalkstein & Greene, 2009). This highlights the significance a system like PWWS can have to reduce heat-related mortality due to climate change.

There are several studies that focused on air pollution and health co-benefits provided by climate change policies. Aaheim et al. looked at several policies in Hungary that aimed at reducing air pollution over a 5-year period. The annual health benefits from applying such policies were, on average, $648 million, with a range of $370 million to $1.2 billion (Aaheim, A, & Seip, 1999). Aunan et al. (2004) studied six policies to reduce coal use in China. The results across the six policies were local health benefits between $32.4 and $120.4 per ton of CO2 reduced, representing a positive net benefit and a win-win situation in a social sense (Aunan, Fang, Vennemo, Oye, & Seip, 2004). Another study in China (Wang, Ogden, & Sperling, 2008) looked at policies that would reduce GHGs by 10% by 2010 and by 15% by 2020. The benefits were 1,500 to 530,000 avoided deaths by 2020.

Cifuentes L, Borja-Aburto VH, Gouveia N, Thurston G, and Davis DL (2001a; 2001b) studied four large cities: Mexico City, São Paulo, Santiago, and New York, and the potential use of policies aimed at reducing GHGs. The predicted benefits included 64,000 avoided deaths, 65,000 avoided cases of chronic bronchitis, and 37 million avoided personal days of restricted activities in 2020. Another study in Mexico City by McKinley et al. (2005) looked at five control measures to reduce air pollutants. The results showed nearly $10 million benefits each year as well as 100 avoided deaths, 700 avoided cases of bronchitis, and over 500,000 minor restricted activity days avoided annually.

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Van Vuuren et al. (2006) analyzed three climate policies in Europe between 1998 and 2020. The cost savings were €2.5-7 billion (approximately 2008 US$3.14-8.79 billion) (van Vuuren et al., 2006; Williamson, 2009) and pollution was reduced by 15% for SO2. In Russia, Dudek et al. (2003) found that climate policies could save between 30,000 to 40,000 lives annually by 2010 (Dudek, Golub, & Strukova, 2003). Lastly, Burtraw et al. (2003) looked at CO2 mitigation policies in the energy sector in the United States from 2000 to 2010 and total ancillary benefits ranged between $12-14 for a $25 carbon tax (Burtraw et al., 2003).

While the majority of studies were made in a single country, others focused on global climate policies. West et al. (2006) analyzed policies aimed at reducing methane (O3) from 2010 to 2030. By 2010, 20% of methane had to be reduced and sustained by 2030. The results showed approximately 30,000 avoided deaths worldwide by 2030 and nearly 37,000 between 2010 and 2030. Benefits were approximately $240 per ton of methane, which exceeded the marginal cost of methane reduction (West, Fiore, Horowitz, & Mauzerall, 2006). Below is the summary of these studies. Table 10: Studies investigating the air pollution and health co-benefits from Climate Change policies

Study Author Area and Timeframe Results

Dessus and O’Conner, 2003 Santiago, Chile (2003) 20% CO2 reduction leads to no net welfare loss. 10% CO2 reduction closer to

optimal levels. Dudek et al. 2003 Russia (2008-2012) 30,000 to 40,000 lives

saved annually by 2010. McKinley et al. 2005 Mexico City About US$10 million

benefits each year and 100 deaths, 700 cases of chronic

bronchitis, and over 500,000 minor restricted activity days (MRAD)

avoided annually. Van Vuuren et al. 2006 Europe (1990-2010) Cost savings of €2.5-7

billion. Reduced pollution levels, such as 15% for

SO2. Wang and Smith 1999 China (2000-2020) 1,500 to 530,000 deaths

avoided by 2020, depending on policy scenario and

assumptions. West et al. 2006 Global (2010-2030) Benefit of ~$240 per ton of

methane, which exceeded the marginal cost of methane reduction.

Source: Adapted from Bell et al., 2008.

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V. Conclusion

Human health consists of physical, social and psychological well-being (WHO, 2008)

and it’s expected to be affected by current climate change. People are exposed to climate change through variations in weather phenomenon such as temperatures, sea-level rise, precipitation, and more frequent extreme weather incidents (IPCC, 2007). According to the IPCC’s report, the major impacts climate change can have on human health include: • temperature-related illness and death • extreme weather-related health consequences • air pollution-related health effects • water and food-borne diseases • vector-borne and rodent-borne diseases • effects of food and water shortage • Mental, nutritional, infectious and other health incidents.

Besides all these negative impacts, warmer conditions can also bring benefits. Some of the benefits include fewer winter deaths in temperate climates, increases in food production especially in high latitude regions, and some changes in the range and transmission of malaria in Africa (IPCC, 2007; WHO, 2008). However, the negative impacts are expected to outweigh the positive effects (IPCC, 2007).

To better understand the impacts of climate change on human health, Patz et al. (2000) classifies the harmful exposures as physical, physical/chemical, physical/biological, and sociodemographic (Patz et al., 2000).

Physical effects include number of hot days, extremely cold days, urban island effect, extreme weather events, floods, severe storms, and droughts. These extreme events overwhelm the capacity of people to cope with the situation and produce widespread losses throughout various economic sectors (Patz et al., 2000).

Physical/chemical effects include air pollutant formation and transport and release of toxic chemicals. Weather determines, influences, transports, and diffuses concentrations of many pollutants. Often large high-pressure systems create a temperature inversion that traps pollutants in the Earth’s surface (IPCC, 2007; Patz et al., 2000)(IPCC, 2007; Patz et al., 2000)(IPCC, 2007; Patz et al., 2000). Climate change and its rising temperature will likely increase air pollutants like ground-level ozone and particular matter (PM) and that can lead to severe health consequences.

Physical/biological effects involve disease agents, vectors, and their habitats, altered marine and freshwater ecology, altered food productivity, nutrient value, plant pathogens, and effects on levels of aeroallergens. Climate change is likely to affect the seasonality and distribution of serious infectious diseases. Vector-borne diseases, rodent-borne diseases, water-borne diseases, food productivity, and the levels of allergens are all expected to be aggravated by climate change (Patz et al., 2000).

Sociodemographic effects include forced displacement, overcrowded living conditions, and human conflicts (Patz et al., 2000). Forced migration can be a result of sea level rise and repeated flooding. Rising waters can also lead to salination of coastal freshwater and disturb storm water drainage and sewage disposal. People may have to adjust their clothing to climate change as well as the amount of time spent on outdoor activities (Patz et al., 2000; IPCC, 2007).

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Climate change in Texas In Texas, some of the impacts climate change will have on the population health

include: • More frequent and severe attacks of asthma, an increased occurrence of strokes,

and aggravation of other respiratory illnesses and cardiac problems. • Changes in quality and supply of freshwater. • More accidents and injuries caused by extreme weather events. • Higher health risk for vulnerable populations. • Higher risk of infectious diseases. • Increased number of heat-related illnesses. Warmer temperatures and more frequent heat waves may lead to increased heat-

related mortality and illnesses in the state. Extreme weather events are also likely to increase in frequency and intensity, so hurricanes hitting the Texas coast can become more devastating during the next years. Some populations will also be more vulnerable than others to climate change. Hispanics are the most vulnerable since they have higher exposure to outdoor and indoor pollutants, pesticides, hazardous waste sites, lead, and mercury. Lower income levels, place of residence, and types of occupation make them even more vulnerable to toxins and disease than any other population (Barrows, 2003; IPCC, 2007; Patz et al., 2000).

Demographically, the elderly, children, poor, those with low immune system defenses, those with heart diseases, below poverty line, without health insurance, and receiving Medicaid and Medicare support are the most vulnerable to climate change impacts. Together, children below five years of age and the elderly (those with 65 years old or older) represent 18.5% of Texas population and the poor represent 16.2% (U.S. Census Bureau, 2010).

Two high risk areas in Texas are the Texas-Mexico border region and Texas coastline. The Texas-Mexico border region has poor air quality and sewer systems and 12% of its population does not have access to clean water. These conditions put populations in these areas, especially children, at high risk for health problems. The Gulf coast is one of the most vulnerable areas to climate change in the state and that puts the Texas coastline at high risk as well. Any change that affects the sea, whether it’s the water temperature, wind, currents, nutrient levels, or precipitation level, is of concern to the Texas coast. One example is food-borne diseases transmitted by fish and shellfish in contaminated waters. In the fall of 2000, red tide algae covered 300 miles of Texas coastline and closed oyster beds for weeks to prevent human poisoning from shellfish (Barrows, 2003). In the winter of 2009, the Texas coast saw another episode of red tide were thousands of fish were killed (Burnett, 2009).

Overturning this climate trend requires immediate world-wide action. Its impacts are long-term and continual and should include numerous ethical perspectives such as justice and equity, rights, freedom, and welfare. While there may be some uncertainties about climate modeling, it is clear that human activities have a powerful effect on climate (Stern et al., 2007).

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Cost of Inaction Climate change and its consequences on human health will have and is already

having significant economic impacts in Texas. More frequent and severe weather extremes and more recurrent transmitted infectious diseases will increase mortality, morbidity, and injuries. More money will be spent on human health.

Worldwide, from 1980 to 2004, the economic costs of weather-related natural events were US$ 1.4 trillion (in 2004 US dollars) (Anderson et al., 2005). In the U.S., in 1999, $500 million were spent on health treatments from West Nile virus. Lyme disease costs around $60,000 per case. Asthma costs increased from $4.5 billion in the mid-1980s to over $10 billion in mid-1990s. Heat waves costs include life insurance payments, wildfire deaths, property damage and direct health costs. All these costs and more will increase with the impacts climate change.

Costs of Climate Mitigation Climate change and the severity of its impacts will continue to rise unless the

emission of greenhouse gases is reduced or stabilized. Firm action is needed to delay, stop, or overturn the continuous rise of greenhouse gas emissions (House of Lords, 2005).

Stabilization means reducing annual emissions to the levels that balance the Earth’s natural capacity to remove greenhouse gases from the atmosphere. In the long run, emissions will have to be reduced by 80% of current levels to reach stabilization. The longer before actions are taken, the more drastic the changes will have to be (Stern, 2007). There are several possible emission trajectories with early or late peaks and more gradual or drastic cuts. However, higher cuts have been historically associated with economic recession or turmoil (Stern, 2007). Seeing this, it would be beneficial for Texas to start stabilizing GHG emissions now since later actions are more risky and less economically viable.

Stabilization at 550 ppm CO2e or below is considered achievable and consistent with economic growth. The present world annual costs in US$2005 prices of achieving the 550 ppm target is equivalent to spending $2 to $17 trillion at once today. As an annual flow it would be around $78 to $661 billion annually. Another way of expressing the costs of achieving the 550ppm target is cost per ton of carbon reduced. In this case, the cost is between $18 and $44 tC (Stern, 2007).

Although we are focusing on the costs only, mitigating climate change will reduce mortality and illnesses, improve human health and environmental conditions, and reduce the economic impacts associated with human lives and environmental livelihoods.

Benefits of Climate Mitigation Slowing down or stopping the course of climate change would result in benefits for

human health directly related to decreases in temperature and associated impacts. Climate policies aimed at reducing greenhouse gas emissions would also improve air quality and other ancillary health benefits. Whereas the benefits from climate policies would be felt over the long-run, the ancillary health benefits would be felt in the short-term (Bell et al., 2008).

Ancillary benefits are the side effects of mitigating problems such as air pollution. Sometimes they are called ancillary impacts, meaning they can be positive or negative. To make the comparison of benefits or impacts easier, the outcomes are usually

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converted into economic terms that allow direct comparison between costs and benefits. One way of estimating economic benefits or costs is by attributing a value for saved lives (VSL). The global economic value of loss of life due to climate change ranges from $6 billion to $88 billion, in 1990 U.S. dollar prices (Confalonieri et al., 2007).

According to a working group on public health and fossil fuel combustion, reducing CO2 emissions would prevent 700,000 premature deaths by 2020 (World Resources Institute, 1997; IPCC, 2001). Adopting climate change policies now can bring benefits locally and globally by decreasing particulate air pollution and protecting human health. Over the next two decades at least 8 million of deaths could be avoided worldwide with climate policies (World Resources Institute, 1997).

In the United States, the potential number of lives saved annually by reducing air pollutants equals the number of deaths from HIV or infectious liver diseases in 2000 (note that the study used a conservative approach (World Resources Institute, 1997).

According to two different studies, the average ancillary benefits of reducing CO2 emissions in the U.S. are US$41/tC (in 1996 US$ or US$56.26 in 2008$US) (IPPC, 2001). Consequently, numerous measures are being addressed by several entities and countries to adapt to climate change (Anderson et al., 2005). Texas should adopt and lead such initiatives. Balancing actions that decrease vulnerabilities and facilitate climate’s stabilization should be a standard that can guide public policy, private investment, and insurance policies in Texas.

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