Climate Control and Ozone Depletion
Chapter 19
An Enormous Cloud of Air Pollutants and Ash from Iceland volcano (April 2010)
This dust cloud closedAirports in Europe foralmost one week.
Coal Power Plant emitting green house gas
19-1 How Might the Earth’s Temperature and Climate Change in the Future?
Concept 19-1 The overwhelming scientific consensus is that the earth’s atmosphere is warming rapidly, mostly because of human activities, and that this will lead to significant climate change during this century.
How Do We Know What Temperatures Were in the Past?
Scientists analyze tiny air bubbles trapped in ice cores learn about past:• troposphere
composition. • temperature trends.• greenhouse gas
concentrations.• solar, snowfall, and
forest fire activity.
Estimated Changes in the Average Global Temperature of the Atmosphere
Fig19-2
Carbon Dioxide at highest levels
In 2005, an ice core showed that CO2 levels in the troposphere are the highest they have been in 650,000 years.
The Natural Greenhouse Effect Four major factors shape the earth’s climate:• The sun.• Greenhouse effect that warms the earth’s lower
troposphere and surface because of the presence of greenhouse gases.
• Oceans store CO2 and heat, evaporate and receive water, move stored heat to other parts of the world.
• Natural cooling process through water vapor in the troposphere (heat rises).
Atmospheric Levels of CO2 and CH4, Global Temperatures, and Sea Levels
Fig 19-4
Keeling Curve
IPCC greenhouse gases by source
Carbon Dioxide Trends (IPCC)
Animation: Greenhouse effect
The Atmosphere Is Warming Mostly Because of Human Activities
Intergovernmental Panel on Climate Change (IPCC)• 90–99% likely that lower atmosphere is warming• 1906–2005: Ave. temp increased about 0.74˚C• 1970–2005: Annual greenhouse emissions up 70%• Past 50 years: Arctic temp rising almost twice as fast as the rest
of the earth• Melting of glaciers and floating sea ice• Prolonged droughts: increasing• Last 100 years: sea levels rose 10–20 cm• Warmer temperatures in Alaska, Russia, and the Arctic are
melting permafrost releasing more CO2 and CH4 into the troposphere.
Melting of Alaska’s Muir Glacier between 1948 and 2004
The Big Melt: Some of the Floating Sea Ice in the Arctic Sea
The Scientific Consensus about Future Climate Change
There is strong evidence that human activities will play an important role in changing the earth’s climate during this century.• Coupled General Circulation Models (CGCMs)
couple, or combine, the effects of the atmosphere and the oceans on climate.
Fig. 19-A, p. 502
Sun
Troposphere
Cooling from increase
Aerosols Greenhouse gases Warming
from decrease
CO2 removal by plants and soil organisms
CO2 emissions from land clearing, fires, and decay
Heat and CO2 removal
Heat and CO2 emissions
Ice and snow cover
Shallow ocean
Land and soil biotaLong-term storageNatural and human
emissions
Deep ocean
CGC Models sources
NASA
IPCC Climate Change Model
Comparison of Measured Temperature from 1860–2007 and Projected Changes
Fig 19-b
Intergovernmental Panel on Climate Change (IPCC)Fourth Assessment Report 2007
Click for IPCC web page
Warming of the climate system is unequivocal, as isnow evident from observations of increases in globalaverage air and ocean temperatures, widespreadMelting of snow and ice and rising global average sea level(Figure SPM.1). {1.1}Most of the observed increase in global averageTemperatures since the mid-20th century is verylikely (p = .90) due to the observed increase in anthropogenic GHG concentrations.(Figure SPM.4). {2.4}
IPCC Treatment of Uncertainty
Where uncertainty is assessed more quantitatively usingexpert judgment of the correctness of underlying data, models or analyses, then the following scale of confidencelevels is used to express the assessed chance of a finding being correct: very high confidence at least 9 out of 10; high confidence about 8 out of 10; medium confidenceabout 5 out of 10.Where uncertainty in specific outcomes is assessed using expert judgment and statistical analysis of a body of evidence (e.g. observations or model results), then the following likelihood ranges are used to express the assessed probability of occurrence: virtually certain >99%; extremely likely >95%; very likely >90%; likely >66%;.
IPCC Emissions and Equilibrium Temperatures
IPCC Temperature projections
Is a Hotter Sun the Culprit?
Since 1975• Troposphere has warmed• Stratosphere has cooled
This is not what a hotter sun would do
Changing Ocean Currents
Global warming could alter ocean currents and cause both excessive warming and severe cooling.
Ocean Acidification
Click for Ocean Acidification Network
Click for NRDC Acid Test
FACTORS AFFECTING THE EARTH’S TEMPERATURE
Some factors can amplify (positive feedback) and some can dampen (negative feedback) projected global warming.
There is uncertainty about how much CO2 and heat the oceans can remove from the troposphere and how long the heat and CO2 might remain there.
There Is Uncertainty about the Effects of Cloud Cover on Global Warming
Warmer temperatures create more clouds• Thick, light-colored low altitude clouds: decrease
surface temperature• Thin, cirrus clouds at high altitudes: increase
surface temperature
Outdoor Air Pollution Can Temporarily Slow Global Warming
Aerosol and soot pollutants• Will not enhance or counteract projected global
warming• Fall back to the earth or are washed out of the
lower atmosphere• Reduction: especially in developed countries
DEALING WITH GLOBAL WARMING
Climate change is such a difficult problem to deal with because:• The problem is global.• The effects will last a long time.• The problem is a long-term political issue.• The harmful and beneficial impacts of climate
change are not spread evenly.• Many actions that might reduce the threat are
controversial because they can impact economies and lifestyles.
19-2 What Are Some Possible Effects of a Warmer Atmosphere?
Concept 19-2 The projected rapid change in the atmosphere's temperature during this century is very likely to increase drought and flooding, shift areas where food can be grown, raise sea levels, result in intense heat waves, and cause the premature extinction of many species.
IPCC Projected Regional Impacts
IPCC ImpactsVery likely = 90% probable
Enhanced Global Warming Could Have Severe Consequences
Tipping point and irreversible climate change
Worst-case scenarios• Ecosystems collapsing• Low-lying cities flooded• Wildfires in forests• Prolonged droughts: grasslands become dust
bowls• More destructive storms• Glaciers shrinking; rivers drying up
Projected Effects of Global Warming and the Resulting Changes in Global Climate
Fig 19-7
Severe Drought Is Increasing: The Browning of the Earth
Accelerate global warming, lead to more drought
Biodiversity will decrease
Net Primary Productivity (NPP) will decrease
Dry climate ecosystems will increase
Ice and Snow Are Melting
Europe’s Alps• Glaciers are disappearing
South America• Glaciers are disappearing
Greenland• Warmer temperatures
Areas of Glacial Ice Melting in Greenland during Summer 1982–2007 Increased
Fig 19-c
Sea Levels Are Rising
Projected irreversible effect• Degradation and loss of 1/3 of coastal estuaries,
wetlands, and coral reefs• Disruption of coastal fisheries• Flooding of • Low-lying barrier islands and coastal areas• Agricultural lowlands and deltas
• Contamination of freshwater aquifers• Submergence of low-lying islands in the Pacific
and Indian Oceans and the Caribbean
Areas of Florida, U.S., to Flood If Average Sea Level Rises by One Meter
Fig19-8
Low-Lying Island Nation: Maldives in the Indian Ocean
Permafrost Is Likely to Melt: Another Dangerous Scenario
Carbon present as CH4 in permafrost soils and lake bottoms
2004: Arctic Climate Impact Assessment• 10–20% of the permafrost might melt this century
Effect on global warming – ice reflects heat, land absorbs heat.
Projected Decline in Arctic Tundra in Portions of Russia from 2004 to 2100
Fig 19-10
Global Warming Is a Major Threat to Biodiversity
Most susceptible ecosystems• Coral reefs• Polar seas• Coastal wetland• High-elevation mountaintops• Alpine and arctic tundra
Effects on Biodiversity: Winners and Losers
Possible effects of global warming on the geographic range of beech trees based on ecological evidence and computer models.
Changes in Average Ocean Temperatures, Relative to Coral Bleaching Threshold
Fig 19-11
Exploding Populations of Mountain Pine Beetles in British Columbia, Canada
Climate Change Will Shift Areas Where Crops Can Be Grown
Regions of farming may shift• Decrease in tropical and subtropical areas• Increase in northern latitudes• Less productivity; soil not as fertile
Genetically engineered crops more tolerant to drought
Climate Change Will Threaten the Health of Many People
Deaths from heat waves will increase
Deaths from cold weather will decrease
Higher temperatures can cause• Increased flooding
• Increase in some forms of air pollution, more O3
• More insects, microbes, toxic molds, and fungi
19-3 What Can We Do to Slow Climate Change? (1)
Concept 19-3A To slow the rate of global warming and climate change, we can increase energy efficiency, sharply reduce greenhouse gas emissions, rely more on renewable energy resources, and slow population growth.
DEALING WITH GLOBAL WARMING
Climate change is such a difficult problem to deal with because:• The problem is global.• The effects will last a long time.• The problem is a long-term political issue.• The harmful and beneficial impacts of climate
change are not spread evenly.• Many actions that might reduce the threat are
controversial because they can impact economies and lifestyles.
19-3 What Can We Do to Slow Climate Change? (2)
Concept 19-3B Governments can subsidize energy efficiency and renewable energy use, tax greenhouse gas emissions, set up cap-and-trade emission reduction systems, and help to slow population growth.
DEALING WITH GLOBAL WARMING
Two ways to deal with global warming:• Mitigation that reduces greenhouse gas emissions.• Adaptation, where we recognize that some warming
is unavoidable and devise strategies to reduce its harmful effects.
DEALING WITH GLOBAL WARMING
Governments can tax greenhouse gas emissions and energy use, increase subsidies and tax breaks for saving energy, and decrease subsidies and tax breaks for fossil fuels.
A cash program to slow and adapt to global warming now is very likely to cost less than waiting and having to deal with its harmful effects later.
Avoiding Catastrophe: We Can Reduce the Threat of Climate Change
Input or prevention strategies
Improve energy efficiency to reduce fossil fuel use
Stop cutting down tropical forests
Output strategy• Capture and store CO2
IPCC Climate Change Model
Fig. 19-13, p. 515
SOLUTIONS
Global Warming
Prevention CleanupCut fossil fuel use (especially coal)
Remove CO2 from smokestack and vehicle emissionsShift from coal to natural gas Store (sequester) CO2 by planting treesImprove energy efficiencySequester CO2 deep underground (with no leaks allowed)
Shift to renewable energy resources
Transfer energy efficiency and renewable energy technologies to developing countries
Sequester CO2 in soil by using no-till cultivation and taking cropland out of production
Reduce deforestation Sequester CO2 in the deep ocean (with no leaks allowed)
Use more sustainable agriculture and forestry
Repair leaky natural gas pipelines and facilitiesLimit urban sprawl
Reduce poverty Use animal feeds that reduce CH4 emissions from cows (belching)
Slow population growth
International Climate Negotiations: The Kyoto Protocol
– Treaty on global warming which first phase went into effect January, 2005 with 189 countries participating.
– It requires 38 participating developed countries to cut their emissions of CO2, CH4, and N2O to 5.2% below their 1990 levels by 2012.
– Developing countries were excluded.• The U.S. did not sign, but California and Maine
are participating.• U.S. did not sign because developing countries
such as China, India and Brazil were excluded.
Fifteen Ways to Cut CO2 Emissions
Fig. 19-14, p. 515
Stepped Art
Some Output Methods for Removing CO2 from the Atmosphere and Storing It
Fig19-15
Case Study: Is Capturing and Storing CO2 the Answer?
Problems with carbon capture and storage cont…• Promotes the continued use of coal (world’s
dirtiest fuel)• Effect of government subsidies and tax breaks
• Stored CO2 would have to remain sealed forever: no leaking. This is book’s opinion. Flint does not agree
Some Governments Are Leading the Way
Costa Rica: goal to be carbon neutral by 2030
Norway: aims to be carbon neutral by 2050
China and India must change energy habits
U.S. cities and states taking initiatives to reduce carbon emissions
What Can You Do? Reducing CO2 Emissions
Fig 19-16
We Can Prepare for the Harmful Effects of Climate Change?
Genetically engineer crops more tolerant to drought
Stockpile 1–5 years of key foods
Waste less water
Connect wildlife reserves with corridors
Ways to Prepare for the Possible Long-Term Harmful Effects of Climate Change
Fig19-17
19-4 How Have We Depleted O3 in the Stratosphere and What Can We Do?
Concept 19-4A Widespread use of certain chemicals has reduced ozone levels in the stratosphere, which allows for more harmful ultraviolet radiation to reach the earth’s surface.
Concept 19-4B To reverse ozone depletion, we must stop producing ozone-depleting chemicals and adhere to the international treaties that ban such chemicals.
Fig. 19-18, p. 523
300
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280
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Mea
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1970 1980 1990 2000 2010
260
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Natural Capital Degradation: Massive Ozone Thinning over Antarctica in 2007
Fig 19-19
Science Focus: Rowland and Moline—A Scientific Story of Courage and Persistence
Research• CFCs are persistent in the atmosphere• Rise into the stratosphere over 11-20 years• Break down under high-energy UV radiation• Halogens produced accelerate the breakdown of
O3 to O2
• Each CFC molecule can last 65-385 years
1988: Dupont stopped producing CFCs
Summary of CFCs and Other Chlorine-Containing Compounds that Destroy Ozone
Fig19-d
Natural Capital Degradation: Effects of Ozone Depletion
Fig 19-20
Structure of the Human Skin and the Relationship between UV and Skin Cancer
Fig 19-e
Thin layer of dead cells
Squamous cells Epidermis
Basal layer Sweat gland
Melanocyte cellsDermis
Blood vesselsBasal cell
Hair
This long-wavelength (low-energy) form of UV radiation causes aging of the skin, tanning, and sometimes sunburn. It penetrates deeply and may contribute to skin cancer.
This shorter-wavelength (high-energy) form of UV radiation causes sunburn, premature aging, and wrinkling. It is largely responsible for basal and squamous cell carcinomas and plays a role in malignant melanoma.
Ultraviolet A Ultraviolet B
Fig. 19-E, p. 526
Stepped Art
Basal Cell Carcinoma MelanomaSquamous Cell Carcinoma
Human Health• Worse sunburn• More eye cataracts• More skin cancers• Immune system suppression
Food and Forests• Reduced yields for some crops• Reduced seafood supplies from reduced phytoplankton• Decreased forest productivity for UV-sensitive tree species
Wildlife• Increased eye cataracts in some species• Decreased population of aquatic species sensitive to UV radiation• Reduced population of surface phytoplankton• Disrupted aquatic food webs from reduced phytoplankton
Air Pollution and Materials• Increased acid deposition• Increased photochemical smog• Degradation of outdoor paints and plastics
Global Warming
• Accelerated warming because of decreased ocean uptake of CO2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases
Effects of Ozone DepletionNatural Capital Degradation
Fig 19-20
What Can You Do? Reducing Exposure to UV Radiation
Fig 19-f
We Can Reverse Stratospheric Ozone Depletion
Stop producing all ozone-depleting chemicals
60–100 years of recovery of the O3 layer
1987: Montreal Protocol
1992: Copenhagen Protocol
Ozone protocols: prevention is the key
Animation: How CFCs destroy ozone
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