Climate Change & Ozone Loss Chapter 21

Temperature Changes 900,000 years – alternating cycles of freezing & thawing Glacial period- ice age Interglacial period- between ice ages

Average temperature over past 900,000 years Thousands of years ago Average surface temperature (°C) Present Figure 21-2a Page 463

Temperature change over past 1,000 years Year Temperature change (°C) Figure 21-2c Page 463

Average temperature over past 130 years Year Average surface temperature (°C) Figure 21-2d Page 463

Studying Climate Change Ice cores- drilled from ice – info about tropospheric composition, temperature trends, greenhouse gas concentrations, solar activity, snowfall, forest fire frequency Core samples- into bottoms of lakes, ponds, & swamps – analyze sediment for pollen, fossils, & other clues about plants Infrared sensors – temperatures

Direct measurements about tropospheric temperature, composition, trends Air samples – changes in chemical composition

Natural Greenhouse Effect Warming of Earth’s lower troposphere & surface Widely accepted theory due to numerous lab experiments & measurements of atmospheric temperatures at different altitudes (since 1896)

Natural Cooling Process Large quantities of heat are absorbed by evaporation of liquid surface water Water vapor rises Condenses (clouds) & releases heat higher in the atmosphere

Major Greenhouse Gases Water vapor CO 2

Human Activities & Greenhouse Gases Rise in use of fossil fuels Deforestation & clearing/burning of grasslands to raise crops & build cities Raising of increasing number of cattle & other livestock Cultivation of rice paddies & inorganic fertilizers U.S.- 4.6% of population; 24% of emissions

Signs of Troposphere Warming 20 th century- hottest in last 1000 years Average surface temperature up 0.6°C (1.1°F) – mostly since warmest years since 1980 Melting/shrinking of glaciers & floating sea ice Rising sea level

Changes at the Poles Greater temperature changes Melting & thinning sea ice faster than it is formed Higher albedo – less reflectivity

Figure 21-9 Page 470 Troposphere Aerosols Greenhouse gases Warming from decrease Cooling from increase CO 2 removal by plants and soil organisms CO 2 emissions from land cleaning, fires, and decay Heat and CO 2 removal Heat and CO 2 emissions Ice and snow cover Natural and human emissions Land and soil biotoa Shallow ocean Long-term storage Deep ocean

2001 IPCC Results Latest climate models match records of global temperature changes very closely Most global warming over the last 50 years is due to human activities 90% probability that surface temperature will increase up to 10°F by 2100

Figure Page 471 Year Change in temperature (ºC)

Climate Shift Availability of water resources (evaporation/precipitation rates) Change wind patterns & weather Alter climates (dry/moist areas) Alter ocean currents Shift area of productive farm land Increase average sea level & flood coastal areas, cities, & low-lying islands Change structure & location of biomes * Little time to deal with climate changes

Antarctica Greenland Figure Page 472

Cloud Cover & Climate Change Warming effect- warmer temperatures increase evaporation of surface water & create more clouds Cooling effect- absorbing & releasing heat or by reflecting more sunlight back into space

Air Pollution & Climate Change May increase cloud cover Clouds reflect more sunlight back into space (may counteract the increase of greenhouse gases)

Photosynthesis & Climate Change Increased C0 2 increases the rate of photosynthesis This would remove excess CO 2 from atmosphere & slow global warming

Methane & Global Warming Increased methane would accelerate global warming Sources of methane: Bogs & wetlands – methane hydrates Melting of permafrost in tundra & boreal forests

Decreased deaths from cold weather Increased deaths from heat and disease Disruption of food and water supplies Spread of tropical diseases to temperate areas Increased respiratory disease and pollen allergies Increased water pollution from coastal flooding Increased formation of photochemical smog Human Health Rising sea levels Flooding of low-lying islands and coastal cities Flooding of coastal estuaries, wetlands, and coral reefs Beach erosion Disruption of coastal fisheries Contamination of coastal aquifiers with salt water Sea Level and Coastal Areas Changes in forest composition and locations Disappearance of some forests, especially ones at high elevations Increased fires from drying Loss of wildlife habitat and species Forests Changes in water supply Decreased water quality Increased drought Increased flooding Snowpack reduction Melting of mountaintop glaciers Water Resources Shifts in food-growing areas Changes in crop yields Increased irrigation demands Increased pests, crop diseases, and weeds in warmer areas Agriculture Extinction of some plant and animal species Loss of habitats Disruption of aquatic life Biodiversity Prolonged heat waves and droughts Increased flooding from more frequent, intense, and heavy rainfall in some areas Weather Extremes Increased deaths from heat and disruption of food supplies More environmental refugees Increased migration Human Population Figure Page 475

Atmospheric Warming / Developing Countries Harmful effects of moderate global warming will fall on people & economies in poorer tropical & subtropical nations

Figure Page 475 Less severe winters More precipitation in some dry areas Less precipitation in some wet areas Increased food production in some areas Expanded population and range for some plant and animal species adapted to higher temperatures

What To Do… Do more research before acting (wait-and- see strategy) Act now to reduce risks from climate change brought about by global warming (precautionary principle) Act now as part of a no-regrets strategy

Figure Page 479 Global Warming Solutions PreventionCleanup Cut fossil fuel use (especially coal) Shift from coal to natural gas Improve energy efficiency Shift to renewable energy resources Transfer energy efficiency and renewable energy technologies to developing countries Reduce deforestation Use more sustainable agriculture Limit urban sprawl Reduce poverty Slow population growth Store (sequester) CO 2 by planting trees Sequester CO 2 deep underground Sequester CO 2 in soil by using no-till cultivation and taking crop land out of production Sequester CO 2 in the deep ocean Repair leaky natural gas pipelines and facilities Use feeds that reduce CH 4 emissions by belching cows Remove CO 2 from smokestack and vehicle emissions

Removing CO 2 from Atmosphere Immature trees- only temporary because trees release stored CO 2 back into atmosphere when they die, decompose, or are burned Plants that store in soil (like switchgrass)- warmer temperatures can increase decomposition in soils & return some to atmosphere Deep underground reservoirs- pump into unminable coal seams & abandoned oil fields

Figure Page 480 Tree plantation Coal power plant Tanker delivers CO 2 from plant to rig Oil rig Crop field Switchgrass Spent oil reservoir is used for CO 2 deposit CO 2 is pumped down to reservoir through abandoned oil field Abandoned oil field CO 2 is pumped down from rig for deep ocean disposal = CO 2 deposit = CO 2 pumping

Governments Reducing the Threat Phase in output-based carbon taxes on each unit of CO 2 emitted by fossil fuels (especially coal & gasoline) or input-based energy taxes on each unit that is burned Level economic playing field- greatly increasing government subsidies for energy- efficiency & carbon-free renewable energy technologies, carbon sequestration, more sustainable agriculture, & by phasing out subsidies & tax breaks for using fossil fuels

Technology transfer- governments of developed countries could fund transfer of energy-efficiency & carbon-free renewable energy technologies, carbon sequestration, more sustainable agriculture technologies to developing countries

Buying/Selling Emission Permits Stimulates companies to develop new technologies to reduce greenhouse gas emissions & increase profits Credits are earned by: Improving energy efficiency Switching from coal to natural gas or renewable energies Adopting farming, ranching, soil building, & conservation practices Sequestering CO 2

Disadvantages: Difficult to monitor compliance due to burning of carbon fuels in homes, vehicles, factories, & crop fields Politically difficult for nations to agree on credits & how to divide them

Kyoto Protocol 39 developed countries to cut emissions of CO 2, CH 4, N 2 0 by 2012 Did not require poorer developing countries to make cuts until later Allows emission trading By ratified by 120 countries U.S.- withdrew (GWB) in too expensive & did not require emissions reductions by developing countries such as China & India (large & increasing greenhouse emissions)

New Treaty Include developing countries, set achievable goals, effective trading program for emissions, evaluate strategies for adapting to ecological & economic effects of global warming

Reducing Emissions Large Scale Use natural gas instead of coal Improve energy efficiency in industry & homes Raising taxes on gasoline Government increased R&D & tax breaks for renewable energy Phasing out coal subsidies Shutting down inefficient carbon-free electric plants

Small scale (individuals/schools) Buy carbon-free electricity Buy renewable energy

Figure Page 483 Reducing CO 2 Emissions What Can You Do? Drive a fuel-efficient car, walk, bike, carpool, and use mass transit Use energy-efficient windows Use energy-efficient appliances and lights Heavily insulate your house and seal all drafts Reduce garbage by recycling and reuse Insulate hot water heater Use compact fluorescent bulbs Plant trees to shade your house during summer Set water heater no higher than 49°C (120°F) Wash laundry in warm or cold water Use low-flow shower head

Figure Page 483

Difficulties in Dealing with Global Warming & Climate Change Poorly understood cause/effect Long-term problems Harmful/beneficial effects are uneven Reduction of emissions would take unprecedented international response

Stratospheric Ozone Depletion Thinning of ozone layer Serious threat to humans, other animals, & primary producers

Chemical Causes CFCs Freons Used for: Coolants Propellants Cleaners Fumigants Packaging bubbles HBCFs- fire extinguishers HCl- from space shuttles

How they work… Insoluble in water & chemically unreactive so they remain in troposphere Lifted into stratosphere by convection, random drift, & turbulence in troposphere Break down in stratosphere under UV radiation Releases ions that accelerate the break down of ozone

Seasonal Depletion of Ozone Upper stratosphere over Antarctica disappeared during late winter & spring

Figure Page 486 Effects of Ozone Depletion Natural Capital Degradation 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

Cancers Squamous cell skin cancer- cells in upper layer of epidermis; caused by exposure to sunlight or tanning lamps (UVB) Basal cell skin cancer- lower epidermis cells (UVB) Malignant melanoma- occurs in pigmented areas such as moles; grows quickly & can spread to other body parts

Figure Page 488 Reducing Exposure to UV-Radiation What Can You Do? Stay out of the sun, especially between 10 A.M. and 3 P.M. Do not use tanning parlors or sunlamps. When in the sun, wear protective clothing and sun– glasses that protect against UV-A and UV-B radiation. Be aware that overcast skies do not protect you. Do not expose yourself to the sun if you are taking antibiotics or birth control pills. Use a sunscreen with a protection factor of 15 or 25 if you have light skin. Examine your skin and scalp at least once a month for moles or warts that change in size, shape, or color or sores that keep oozing, bleeding, and crusting over. If you observe any of these signs, consult a doctor immediately.

Restoring the Ozone To 1980 levels – 50 years To 1950 levels – 100 years

Policies for Emission Reduction Montreal Protocol – 1987; 37 nations signed treaty to cut CFC emissions by 35% by 2000 Copenhagen Protocol – 1990; 96 countries; amendment which accelerated the phasing out of key ozone-depleting chemicals

Results Ozone depletion in stratosphere has been cooling troposphere & has helped offset (or disguise) 30% of warming from greenhouse gas emissions Precedent for global cooperation & action to avert potential disaster

International Treaty Convincing & dramatic scientific evidence of serious problem CFCs produced by small number of international companies Certainty that CFC sales would decline unleashed economic & creative resources of private sector to find profitable substitute chemicals