Chap 19 Climate Change and Ozone Depletion

8/8/2019 Chap 19 Climate Change and Ozone Depletion

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Lilian Ayala

Chap 19 Climate Change and Ozone Depletion

19-1 How Might the Earths Temperature and Clime Change in the Future?

y Atmosphere experiences global cooling and global warmingy Glacial and interglacial periods alternating cycles of freezing and thawingy We live in a interglacial periody Greenhouse effect: warms earths lower atmosphere; happens when heat helps vibrate the

greenhouse gases and allows them to release infrared radiation at longer wavelengths intothe lower atmosphere

y The radiation interacts with air molecules increasing their kinetic energy thus warmingthe lower atmosphere and earths surface

y First to recognize this: Svante Arrhenius 1896y Without the greenhouse effect the world would be cold and uninhabitabley Since the beginning of the Industrial Revolution 275 years ago, humans have

significantly increases the greenhouse gases emitted into the atmosphere

yIncrease come from: (CO2 agriculture, deforestation, burning fossil fuels) (methane:creating landfills, raising cattle and sheep (methane), and constructing reservoirs behind

large dams in tropical countries) (Nitrous Oxide: fertilizers)

y Try prevent CO2 exceeding the 450 ppm, threshold or irreversible tipping pointy Evidence:

o 1906-2005 average global surface temp risen by .74 degrees Celsius (1.3 F) Most taken place since 1980

o Annual greenhouse gas emitted from human activities rose 70% 1970-2005;Average CO2 concentrations higher than they have been in 650,000 years(800,000 years to 2007 study)

o Arctic temps risen almost twice as fast than rest of the world (last 50 years)o G

laciers and floating sea ice melting and shrinking, changing rainfall patterns;extreme and prolonged droughts increasingo During last cent, worlds average sea level rose 10-20 cm (4-8 in)

y feed back: amplify (positive) or dampen (negative)y Although suns outputs have effected earths temp before, this could not be from a hotter

sun because:

o Troposphere is warm while stratosphere is cooledo If sun were to emit higher output, the whole atmosphere would be effected and

heated throughout

y Ocean absorbed half of the carbon dioxide released since the Ind Revoy Some of this is converted to insoluble carbonated salts buried in bottom sedimentsy Solubility of co2 decreases as ocean temp increasesy Thus ocean water heating up can dissolve co2 to be released into the atmospherey Worlds ocean appear to absorb less Co2 from atmosphere as they warm, from 2007

study, Southern Ocean around Antarctica has dropped since 1981

y This helps rise acceleration of CO2 in atmosphere, causing warm more rapidly in anotherpositive feedback loop

y The high levels of CO2 in ocean has increase the acidity of oceans; thus effecting thefishies


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y Acidity reduces ability of ocean regulating atmospheric warming and climate change byremoving CO2 from lower atmosphere and storing as bottom sediments; thus can

accelerate global warming and climate change in another positive feedback loop

y Unknown in global climate models is effect that changes in global distribution of cloudmight have on atms temp

y Warm temp increase evaporating of surface water thus more cloudsy Two effect:

o Increase in think and continuous light colored clouds at low altitudes thus coulddecrease surface warming by reflecting more sunlight into space

o Or thin discontinuous cirrus clouds at high altitudes warming the loweratmosphere

y The wispy condensation trail (contrails) left behind by jet planes can turn into cirrusclouds thus release heat into upper troposphere

19-2 What Are Some Possible Effects of a Warmer Atmosphere?

y Scientist concerned over how fast is happening not over the fact that it is happening andincreasing

y Climate models indicate: where food can be grown, how much can be grown, which areaswill suffer flooding and droughts, and we have to deal with this in warp speed

y If we reach the tipping point, it will be to late to reverse the catastrophic changes for tensand thousands of years

y Worst Case Scenarios:o Ecosystems collapsing, low-lying cities being flooded, forest consumed by vast

wildfires, grass lands drying up and turning into dust bowl, rivers dry upo 102states high risk of becoming failures because the key resources will shrink

(food, water, and land) due to climate change

o Browning of the Earth: Drought occurs because evaporation from increased temp greatly exceeds

precipitation for a prolonged period Less moisture in soil, water will decline, primary productivity will fall,

trees and plants slow reducing CO2 removal, biodiversity fall; savannas,chaparral, and deserts increase

Prolong droughts over decades create conditions which will feedbackpositively thus accelerating global warming

o Ice and Snow Caps Melting Light colored snow and ice help reflect solar energy; it melting helps

expose dark land and sea thus absorbing more solar energy Arctic sea ice melting; reducing long term average rainfall and snowfall or

increase long-term average precipitation thus flooding But since sea ice floats, it doesnt contribute to rising sea level when melts Rise of sea level comes from the melting of land based ice (Greenland) Mt glaciers affected by:

y Average snowfall (adding to mass during winter and average warmtemps, spur their melting during summer)


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y Glaciers provide a major source of water, ex: Ganges and Yellowand Yangtze

o Sea Levels rising Glaciers (land based such as Greenland) keep melting: thus adding to sea

levels rising W

ill cause:y Degradation/destruction of 1/3 worlds estuaries, wetlands, and

coral reefs

y Disruption of fisheriesy Sloping coastlines (ex: Florida)y Flooding of agriculture low lands and deltas near coasts where

much of worlds rice is grown

y Contamination of freshwater coastal aquifersy Submergence of low lying islands

o Melting permafrost Helps emit methane thus another positive feedback loop

o Changing Ocean Currents Deep and shallow ocean currents connected like a giant conveyor belt:

transferring CO2, warm/cool water

Melting of land based glaciers and increased N. Atl rainfall will disruptconveyor belt

o Extreme Weather Other areas because warmer atmosphere can hold more moisture,

experience increase flooding and prolonged precipitation Hypothesize: warmer water in Atl increase vertical wind shear (difference

in wind direction or speed at diff altitudes) thus can help inhibit hurricaneformation

o Biodiversity Global warming alters ecosystem services thus affecting animal and plant

species

Hardest hit: in colder climates Forest fires increased because of heat

o Farming Farmers face dramatic shifting climates and faster hydrologic cycle Productivity most in decline: SE Asia, and C. America

o Health of People CO2 rich world great place for insects, microbes, toxic molds, fungi that

make you sick

Higher atmo temps increase air pollution; speed up rate of chemicalreactions that produce ozone and other chemicals in photochemical smog19-3 What Can We Do to Slow Climate Change?

y Difficult because: global problem, effects will last a long time, problem is longer termpolitical issue, harmful and beneficial impacts of climate change are not spread evenly,solutions disrupt economies and lifestyles


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y Three major input or prevention strategies:o Improve energy efficiency to reduce fossil fuel useo Shift from nonrenewable carbon based fossil fuels to a mix of carbon free

renewable resources

o Stop cutting down tropical forestsy Output strategy:o Keep burning but capture and store as much co2 possible in soil, vegetation,

underground, and deep ocean and hope it never leaks out

y Help reduce poverty: decrease need of poor to clear more land for crops and fuelwoody 15 wedges:

o Increase average fuel economy to 60 mpg (2057)o Cut average distance of cars in 2057 to 5000 miles per yearo Cut electricity by 25%o Increase coal fired power plants efficiency 40 to 60%o Increase solar power 700 foldo Increase wind power 25 foldo Increase wind power 50 foldo Increase ethanol biofuel prod. 50 fold by growing crops on 1/6 of worlds croplando Replace 1400 coal fired plant to natural gas fired plantso Displace coal fired plants by tripling electricity production from nuclear power

plants

o Stop all deforestationo Use conservation tillage on all croplando Install carbon capture and storage at 800 large coal fired plantso Install CCS at enough large coal fired plants to produce hydrogen for 1 milli fuel

cell cars

o Install CCS at enough coal to syngas plants to produce 30 milli barrels ofsynfuels per day

y Output: massive global tree planting programo Though when they die they will emit that stored CO2 back into the atmosphere

y Carbon capturing is a geo engineering schemeo Most scientist oppose because effects unknowno Scientist suggest using balloons, large jet planes, giant cannons to inject sulfate

particles into stratosphere where they might reflect some incoming sunlight intospace thus cooling troposphere

y Government can help:o Strictly regulate carbon dioxide and methane as pollutantso Carbon taxeso Levy energy taxes on each unit of fossil fuel that is burnedo Decreasing taxes on income, wages, and profits to offset taxeso Tax pollution, not payrolls and profito Cap and trade approach: permits to emit pollutants or trade their permits in

marketplace: advantage over taxes but hard to manageo Level the economic playing field: increasing govt. subsidies to business and ind to

encourage use of energy-efficiency tech, carbon-free renewable energy sources,more sustainable agriculture


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o Technology transfer: govt. help developing countries to replace their old bad techfor new green tech

o The Kyoto Protocol: Dec 1997, meet for treaty to slow climate change Effect Feb 2005 w/ 174 (not US)

Allows trading of greenhouse gas emissions among participating countries US withdrew because it would harm us economy, also didnt require

emission reductions by rapidly developing countries (China, India)

y Schools and Companieso Alcoa DuPont IBM Toyota GE J&J Volvo BP (lol) Wal-Marto Schools:

Buying/producing renewable energy Wind power

19-4 How Have We Depleted Ozone in Stratosphere and What Can We do about it?

y Lower stratosphere keeps 95% of suns UV rays from reaching earthy Ozone hole: more accurate ozone thinning, disappeared in upper stratosphere in

Antarctica

y CFS (chlorofluorocarbon) inexpensive to manufactureo Found in aerosols, refrigerators, cleaners, etco Destroy ozone

y HBFCs (hydrobromoflurocarbons) fire extinguishers, methyl bromide, hydrogenchloride, cleaning solvents

y Montreal Protocolo Treaty to cut emissions of CFCs

y Copenhagen Protocolo Accelerated the phase out of key ozone depleting chemicals

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Chap 19 Climate Change and Ozone Depletion