HEALTH EFFECTS OF CLIMATE CHANGE

Framework

• Introduction• Important definitions• What are the climate changes?• Health impact of climate changes• Mechanism/ pathway health effect of climate change• How much disease would climate change cause?

» Global» Regional» India

• Monitoring • Steps to minimize

INTRODUCTION

• Weather• Climate • El Nino Southern Oscillations • Precipitation

Definitions

HISTORY

• Ancient scripts

• Hippocrates (about 400 BC)

• Robert Plot (1683–84)

• 1988 - World Meteorological Organization (WMO) United Nations Environment Programme (UNEP) established the Intergovernmental Panel on Climate Change (IPCC)

– 1st report (1991)– 2nd report (1996)– 3rd report (2001)– 4th report ( 2007)

What are climates changes ?Figure 1.1. Variations in Earth's average surface temperature, over the past 20,000 years

Changes in temperature, sea level & northern hemisphere snow cover

Causes of climate change

• Green house effect• Industrialization• Automobiles use• Deforesting• Urbanization• Increase land use

Vulnerability Population

• All most all• Old age and children• Pre-existing morbidity• Poor socioeconomic status• Housing conditions• Prevalence of air conditioning• Behavior (e.g. clothing)

PATHWAY BY WHICH CLIMATE CHANGE AFFECTS HUMAN HEALTH

Table 2: Mechanism by which above-average rainfall can affect health

Table 3: Mechanism by which below –average rainfall can affect health

Health effects of climate change

• Direct effects on health

– Exposure to weather extremes (heat waves, winter cold)– Increases in other extreme weather events (floods, cyclones, storm-surges,

droughts)– Increased production of certain air pollutants and aeroallergens (spores and

moulds)

• Indirect effects on health

– Affect transmission of many infectious diseases – Vector-borne infectious diseases– Water-borne infectious diseases– Food production and supply -Regional food productivity (especially cereal grains)– Effects of social and economic disruptions

IPCC 4th assessment report

•Some extreme weather events have changed in frequency and/ or intensity over the last 50 years: It is very likely that cold days, cold nights and frosts have become less frequent over most land areas, while hot days and hot nights have become more frequent.

• It is likely that heat waves have become more frequent over most land areas.

• It is likely that the frequency of heavy precipitation events (or proportion of total rainfall from heavy falls) has increased over most areas.

• It is likely that the incidence of extreme high sea level has increased at a broad range of sites worldwide since 1975.

(IPCC, 2007)

Climate Change & Health

Climate ChangeImpacts

Physical systems(ice, rivers, etc.)

Biological & seasonal cycles

Economy: infrastructure, output, growth

e.g. prime focus of Stern Report (UK, 2006)

Human Health:• Injuries/deaths• Thermal stress• Infectious diseases• Malnutrition• Mental stresses• Conflict, drugs, etc.

Indirect impacts Wealth (and distribution);

local environment; etc.Direct health impacts (heat, extreme events, etc.)

Food yields

Exposure to weather extremes (heat waves, winter cold)

Two categories:• Based on simple climate statistics(e.g. very low or very high temperatures)• More complex, event driven extremes(eg. droughts, floods or hurricane)

• Increases mortality –specially older age group with preexisting morbidity & urban poor.

• Effect exacerbate by increase humidity & air pollution• Cities with un adopted architecture & limited air conditioning • Warmer winters – fewer deaths

• Extream events – storms, flood, drought & cyclones loss of shelter; population displacement; contamination of water supplies; loss of food production (leading to hunger and malnutrition); increased risk of infectious disease epidemics (including diarrhoeal and respiratory diseases); and damage to infrastructure for provision of health services

Temperature extremes: heat waves and cold spells

• High temperatures cause – heatstroke -increases blood

viscosity - heart attack or stroke.

• cold related mortality- respiratory infections increased blood pressure and fibrinogen levels.

The impact of heatwave events on mortality

• 1995- heatwaves in chicago, USA- 514 & 3300 emergency admission • Death d/t- cardiovascular, cerebrovascular respiratory disease• 1987 heatwaves- in Athens –926 deaths• Estimation was 2000• Overall under estimation – death due to other ds increeses• 1995 uk- 619

• India 1998 – 2600 deaths over 10 week • In ores – 1300 ->49.5Deg cent• Exacerbates reccurent power failure, affected cooling system, & hospital

services • Times of India (28/05/10): The killer heat wave is taking a toll. About 134

people have died this summer including 34 in Vidarbha, five CRPF jawans in Gwalior and seven in Gujarat in the past 24 hours. While 13 people have died in Jaipur in the past two days, the death toll in Vidharbha crossed 70 in the last three days.

Winter mortality

• Temperate country- > 10-25% deaths more than summer

• Causes of winter death- cardiovascular, cerebrovascular, circulatory & respiratory diseases, Influenza

• Heating system & clothing

• Elderly > 75yrs – 30 %

Extreme Weather-Related Health EffectsExtreme Weather-Related Health Effects

19

Hurricanes

Floods

Wildfires

Physical injury

Deaths

Mental Health Effects

Diarrheal Illnesses

dissemination of dangerous chemicals

from storage sites and waste disposal

sites into flood waters

Respiratory Illnesses

Decreases in nutritional status,

Drou

ght

Forest fires & smoke

• Direct effects - Burns and smoke inhalation

• Loss of vegetation -- soil erosion ----risk of landslides,

(often exacerbated when an urban population expands into surrounding hilly and wooded areas)

Air pollution

• Earlier onset of pollen season• Birch tree – pollen production in increasing

temperature

• Increased CO2 and temperature – Increase pollen production/Increased pollen

counts– Increase length of pollen season

• Increase in allergenic reactive

• 1997 SEAR & Americas: increase respiratory & eye symptoms

• Malasia : increase 4 fold respiratory disease Decrease in 14 % lung function

Source: JL Gamble, et al., 2008. USEPA Report. 21

Table : Examples of environmental changes and possible effect on infectious diseases

Climate change & infectious diseases

Vector-borne infectious diseases

• Vector-borne disease transmission is sensitive to temperature fluctuations

• Well-studied relationship- Rainfall & diseases spread by insect vectors• Mosquitoes: malaria & viral diseases (dengue & Yellow fever)• Heavy rain –create/wash away breeding sites • Increases temperature–

Reduce breeding time

Decrease incubation period of pathogen (e.g. malaria parasite, dengue or yellow fever virus)

Affect the behaviour of the vector & human populations,

Affecting probability of transmission.

Malaria

• Very high temperatures - lethal to Mosquito & Parasite

• At low temperatures , small increase in temperature can greatly increase risk of malaria transmission

• Drought in previous year -Increased malaria mortality (decrease infection, increase susceptibility due to malnutrition, decrease herd immunity – subsequent years increase in vulnarable population)

• 1877 El Niño in India: Famine caused excess mortality due to epidemics of malaria,. Many deaths occurred after the end of the drought; the proximate cause was malaria when drought-breaking rains increased vector abundance, exacerbated by population movement and the concentration of people in feeding camps

Dengue

• Seasonal & associated with warmer, more humid weather• Increased rainfall in many locations can affect the vector density

and transmission potential. A study of dengue in Viet Nam, found that the number of cases increased in El Niño years.

• Positive associations between El Niño and dengue epidemics in French Guyana, Indonesia, Colombia and Suriname, regions that experience warmer temperatures and less rainfall during El Niño years.

• Many countries in Asia experienced an unusually high

level of dengue and dengue haemorrhagic fever in 1998, some of which may be attributable to El Niño-related weather.

Effects of Temperature Rise on Dengue Transmission

Shorten viral incubation period in mosquito

Shorten breeding cycle of mosquito

Increase frequency of mosquito feeding

More efficient transmission of dengue virus from mosquito to human

Water-borne infectious diseases• Heavy rainfall -transport terrestrial microbial into drinking-water sources-outbreaks

of crytosporidiosis, giardiasis, amoebiasis, typhoid & other infections

• Floods - contamination of public water supplies with both bacteria and parasites as surface discharge flows into rivers and reservoirs, increasing biotic reservoir of infectious agent (cholera)

• Drought can increases concentration of pathogens in limited water by decreasing amount of water in a river or a pond & thus raising concentration of bacteria (typhoid).

• Reduction of clean water - leading to skin infections.

• Diarrhoeal illness• Cholera epidemics associated with positive surface

temperature in coastal & around inland lake waters. • Epidemiological evidence has pointed to a widespread environmental cause for

recent outbreaks of cholera, rather than a point source contamination as seen in Peru in 1991 and East Africa in 1997/98.

Table : Water and food-agents: connection to climate

Rodent born diseases

• Rodent populations increase in temperate regions following mild wet winters

• A study found that human plague cases in New Mexico occurred more frequently following winter-spring periods with above average precipitation

• Ticks - climate sensitive • Drought conditions had reduced populations of the rodents’ natural

predators; subsequent high rainfall increased food availability in the form of insects and nuts

• Drought may increase human contact

Water and Food-borne Disease:Water and Food-borne Disease:Climate-Susceptible Pathogens Climate-Susceptible Pathogens

Rising temperatures

Increasing rainfall

Shifts in

reservoir ranges

Sea level changes

Salmonella X X X

Campylobacter X X X

Vibrio X X X

Leptospira X X

Enteroviruses X X

Naergleria fowleri X

Cryptosporidium X X

Giardia X X30

Food production, supply & malnutrition

• cereal grain production—an important indicator of total food production

• Climate change may affect this availability through the broadly negative effects of changes in temperature and precipitation

• Increases prevalence of malnutrition

Effects of social and economic disruptions

• Population displacement physical and mental health problem

• Social mechanisms – severe social disruptions, local economic decline and population displacement- island and coastal populations

Important & difficult to quantify: for example, droughts and floods often cause population displacement

• Outbreaks of infectious disease are common in refugee populations due to inadequate public health infrastructure, poor water and sanitation, overcrowding and lack of shelter, more prone to malnutrition

Health effects of Ozone depletion

Fig : Layers of the earth’s atmosphere

Stratospheric ozone depletion, ultraviolet radiation &health

Effects on skin• Malignant melanoma• Non-melanocytic skin cancer –basal cell carcinoma, squamouscell carcinoma• Sunburn• Chronic sun damage• PhotodermatosesEffects on the eye• Acute photokeratitis andphotoconjunctivitis• Climatic droplet keratopathy• Pterygium• Cancer of the cornea andconjunctiva• Lens opacity (cataract) – cortical,posterior subcapsular•Uveal melanoma• Acute solar retinopathy•Macular degeneration

Effect on immunity and infection• Suppression of cell mediated immunity• Increased susceptibility to infection• Impairment of prophylactic immunization• Activation of latent virus infectionOther effects• Cutaneous vitamin D production- prevention of rickets, osteomalacia & osteoporosis- possible benefit for hypertension,ischaemic heart disease & tuberculosis- possible decreased risk for schizophrenia, breast cancer, prostate cancer- possible prevention of Type 1 diabetes• Altered general well-being - sleep/wake cycles- seasonal affective disorder- moodIndirect effects• Effects on climate, food supply, infectious disease vectors, air pollution, etc

How much disease would climate change cause?

Table : Estimates for the impact of climate change in 2000 in thousands of DALYs, burden for specific diseases

Source: World health report 2002

Cartogram: (Selected) health impacts of climate change

Density-equalling cartogram: Patz, Gibbs, et al, 2007.

WHO regions scaled according to estimated mortality (per million people) in the year 2000. Based on burden-of-disease attribution to the climate change that occurred from 1970s to 2000 (McMichael et al., 2003).

Malnutrition > diarrhoea > malaria > floods

Annual mean temperature in India2009 hottest year !!

(Source: Indian Metereology dept report)

Malaria incidence in India

Current Burden of Climate-Sensitive Health Outcomes

•Malaria epidemic in Surat following heavy rainfall in year

•Mumbai - experienced 944 mms of rainfall on July 26 &27,2005; > 1,000 deaths

•2006- Surat, Barmer( Raj) & Srinagar experienced serious floods during monsoon •Consecutive droughts between 2000 and 2002 in Orissa affected 11 million people

•Deaths due to heatstroke & cold reported every year

DATE AREA CASUALTY 1998 Orissa 6501998 India 13002000 Rajasthan 1625Mid April – 3rd wk May 2002 India 1000May 2003 India 1500

Table: Mortality due to heatwaves india

Source: De at al,2005

DATE AREA CASUALTY17-18 Sept. 1880 UP 150July to Aug ) Andhra Pradesh 109 people diedAug. 3rd week to Sept 1988

ssam 167 persons died

June 1st & 2nd 14-16 July 1994

Kerala 209 human lives lost.

26 to28 Aug. 2000 Andhra PradeshHyderabad

131 persons died.

Source: Severe Rainstorms of India, IITM, Pune

• Climate change induced decline in cultivatable land and water

shortage leading to decreased agricultural production will

further cause food shortage and malnutrition especially in

vulnerable population

Impact on nutrition in India

Monitoring the health effects of climate change

Issues and Challenges

•Global warming- global issue & needs coordinated continuous global efforts

•WHO and member countries need to play a proactive role

•Strengthening inter-sectoral coordination

•Improved surveillance and monitoring

•Promotion of research

•Community involvement

Recommended future steps

•Increase in active global disease surveillance. •Continuation of epidemiological research into associations between climatic factors and infectious diseases.•Assessment as a multidisciplinary activity

•Further development of comprehensive models

•Improvements in public health infrastructure.

•Stakeholder engagement•Evaluation of adaptation options•Formulating a research agenda•Increasing public awareness: importance of communicating assessment results•Building the bridge from science to policy policy-focused assessment

Task for public health science

CC and Health: Main Types of Adaptive Strategies

Public education and awareness

Early-alert systems: heatwaves, other impending weather extremes, infectious disease outbreaks

Community-based neighbourhood support/watch schemes

Climate-proofed housing design, and ‘cooler’ urban layout

Disaster preparedness, incl. health-system ‘surge’ capacity

Enhanced infectious disease control programs

vaccines, vector control, case detection and treatment

Improved surveillance:

Risk indicators (e.g. mosquito numbers, aeroallergen concentration)

Health outcomes (e.g. inf dis outbreaks, rural suicide rates, seasonal asthma peaks)

Appropriate workforce training and mid-career development

REFERENCES