Chapter 19 Global Change

1. Chapter 19 Global Change

2. Global Change • Global change- any chemical, biological or physical property change of the planet. Examples include cold temperatures causing ice ages. • Global climate change- changes in the climate of the Earth. • Global warming- one aspect of climate change, the warming of the oceans, land masses and atmosphere of the Earth.

3. The Greenhouse Effect • When radiation from the sun hits the atmosphere, 1/3 is reflected back. • Some of the UV radiation is absorbed by the ozone layer and strikes the Earth where it is converted into low-energy infrared radiation. • The infrared radiation then goes back toward the atmosphere where it is absorbed by greenhouse gasses that radiate most of it back to the Earth.

5. Greenhouse Gases • Water vapor • Carbon dioxide • Methane • Nitrous oxide • Ozone

6. Methane 1)From anaerobic decompositiion (swamps, rice paddies, termites, cows), leaks in pipeline 2) 25X more effective than CO2per molecule (why is CO2 most important greenhouse gas?) 3) Last 9-15 years in troposphere 4) Methane hydrate (stable complex below tundra)

7. Nitrous Oxide (NO2) 1) Traps heat in troposphere and depletes ozone in stratosphere 2) Released from nylon production, burning biomass and coal, breakdown of nitrates (fertilizer, waste) 3) 300 X more effective than CO2 per molecule 4) Lasts 113 years in atmosphere

8. Based on data from layers in glaciers, scientists know during last 800,000 years: 1. Several ice ages, each about 100,000 yrs, occurred 2. Interglacial warm periods are about 10 - 12,000 yr 3. Present one started 10,000 years ago 4. During last one NY state was under 1 mile of ice 5. When ice melted, ocean level rose 100 meters

9. Ice core analysis Air trapped in bubbles in glaciers shows: 1) water vapor concentration has stayed constant but, 18601995 [CO2] 280 ppm 364 ppm see graph p 532 a) CO2 level has corresponded to temperature levels during past 400,000 yrs (p531) -humans appeared 60,000 years ago

11. Future 1. Intergovernmental panel on climate change (IPCC) states mean temperature will rise 1-3.5oC between 1990 to 2100 2. Northern hemisphere warms faster (more land) 3. As temperature rises, evaporation rises, precipitation increases, more heavy rains and snows 4. Due to expansion mostly, ocean level could rise 23 inches (1900 - 2100)

12. Implicated in global warming 1. Temp changes ---> natural fluctuations 2. During sunspot cycles, energy output is increased 3. Oceans a) absorb heat (mixing with colder, lower layers is slow) b) dissolve CO2, but solubility decreases as temp increases, pos feedback loop c) ocean currents distribute heat (Gulf Stream) d) temp up---> photosyn up certain phytoplancton ---> aerosols ---> cooling so neg feedback

13. Human response • Temp up ---> air cond up ---> fossil fuel consumption up ---> CO2 up

14. Effects of a Warmer World 1. If slow ---> organisms can relocate, if too fast ---> no time to relocate 2. Climate bands move north a) ok if ... 1) soil is good 2) money is avail for infrastructure (grain storage, irrigation) b) N.A. ---> Canada ... no China ---> north ... yes Ukraine ---> Siberia ... no

15. Effects of a Warmer World 3. Rising sea level ---> flood productive productive wetlands 4. Increasing ocean temp ---> bleach coral reefs 5. Lakes, streams dry up ---> pop moves 6. Trees may not be able to move north fast enough 7. Drying ---> wildfires 8. Biodiversity down b/c no time for migration 9. Rising sea level ---> lowlands and deltas in China. India and Bangladesh flooded a) The Maldives become submerged a) Netherlands needs $ 3-5 trillion to raise dikes

16. Effects of a Warmer World 10. temp up ---> wind up ---> hurricanes up or temp up ---> droughts 11. insurance companies signed petition to stop global climate change 12. disease ---> malaria ---> temp zone 13. more fungus ---> water supplies disrupted

17. Solutions 1. Expensive to deal with a) boiled frog syndrome: frog wouldn’t complain until it was too late 2. Natural gas CO2 = 1/2 coal CO2, per joule a) watch pipelline leaks 3. Phase out gov subsidies, phase in carbon tax on coal and oil a) based on CO2 emissions b) reduce other taxes to compensate c) sell greenhouse gas emission credits (Chicago stock exchange)

18. Solutions 4. Provide energy conserv tech to dev countries a) solar cookers 5. technofixes a) add iron to oceans ---> algae pop up ---> photosyn up ---> $ billions/yr b) inject sulfate particulates (like volcanic erupt) ---> pollution, O3 destruction

20. Natural Greenhouse Gases • Volcanic eruptions- mainly carbon dioxide • Methane – from decomposition • Nitrous oxide- from denitrification • Water vapor

21. Anthropogenic Causes of Greenhouse Gases • Burning of fossil fuels • Agricultural practices • Deforestation • Landfills • Industrial production- CFC’s are an example

24. Increasing CO2 Concentrations • David Keeling began measuring CO 2 in 1958.

25. Emissions from the Developed and Developing World

26. Global Temperatures since 1880 • Since 1880 temperatures have increased 0.8°C.

28. Temperatures and Greenhouse Gas Concentrations in Past 400,000 Years • No one was around thousands of years ago to measure temperatures so we use other indirect measurements. Some of these are • Changes in species compositions • Chemical analyses of ice

30. Putting It Together • We know that an increase in CO2 in the atmosphere causes a greater capacity for warming through the greenhouse effect. • When the Earth experiences higher temperatures, the oceans warm and cannot contain as much CO2 gas and, as a result, they release CO2 into the atmosphere.

32. Feedbacks

33. Consequences to the Environment Because of Global Warming • Melting of polar ice caps, Greenland and Antarctica • Melting of many glaciers around the world • Melting of permafrost • Rising of sea levels due to the melting of glaciers and ice sheets and as water warms it expands • Heat waves • Cold spells • Change in precipitation patterns • Increase in storm intensity • Shift in ocean currents

35. Consequences to Living Organisms • Wild plants and animals can be affected. The growing season for plants has changed and animals have the potential to be harmed if they can’t move to better climates. • Humans may have to relocate, some diseases like those carried by mosquitoes could increase and there could be economic consequences. • Misalignment of newborns and food availability (warm spring – earlier leaves on trees – earlier caterpillar peak pop – same hatching date for flycatcher)

36. The Controversy of Climate Change • The fundamental basis of climate change- that greenhouse gas concentrations are increasing and that this will lead to global warming is not in dispute among the vast majority of scientists. • What is unclear is how much world temperatures will increase for a given change in greenhouse gases, because that depends on the different feedback loops.

38. The Kyoto Protocol • In 1997, representatives of the nations of the world went to Kyoto, Japan to discuss how best to control the emissions contributing to global warming. • The agreement was that emissions of greenhouse gases from all industrialized countries will be reduced to 5.2% below their 1990 levels by 2012. • Developing nations did not have emission limits imposed by the protocol.

39. Carbon Sequestration • An approach involving taking CO2 out of the atmosphere. • Some methods include storing carbon in agricultural soils or retiring agricultural land and allowing it to become pasture or forest. • Researchers are looking at cost-effective ways of capturing CO2 from the air, from coal-burning power stations, and from other emission sources. • This captured CO2 would be compressed and pumped into abandoned oil wells or the deep ocean.