1. Global Change Chapter 19

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. 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. http://earthguide.ucsd.edu/earthguide/diagrams/greenh ouse/ http://earthguide.ucsd.edu/earthguide/diagrams/greenh ouse/ The Greenhouse Effect

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

6. Greenhouse Gases Natural Greenhouse Gasses Volcanic eruptions- mainly carbon dioxide Methane – from decomposition Nitrous oxide- from denitrification Water vapor Anthropogenic Greenhouse Gasses Burning of fossil fuels Agricultural practices Deforestation Landfills Industrial production- CFC’s are an example

9. David Keeling began measuring CO 2 in 1958. Increasing CO 2 Concentrations

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11. Emissions from the Developed and Developing World

12. Since 1880 temperatures have increased 0.85°C. Global Temperatures since 1880

14. 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 Temperatures and Greenhouse Gas Concentrations in Past 400,000 Years

15. How We Study Climate Instrumental Records Instrumental Records Climate measurements began in 1860s Climate measurements began in 1860s Data from pre 19 th century is Data from pre 19 th century is Estimates Estimates Extrapolated Extrapolated Interpolated Interpolated We have very accurate data since 1960 We have very accurate data since 1960 Improved instrumentation Improved instrumentation

16. How We Study Climate Historical Records Historical Records Go back a few centuries Go back a few centuries Mostly qualitative Mostly qualitative Books, newspapers, journal articles, personal journals, ships’ logs, travelers’ diaries, and farmers’ logs Books, newspapers, journal articles, personal journals, ships’ logs, travelers’ diaries, and farmers’ logs Paleoproxy records Paleoproxy records Proxy data- not strictly climatic, but provides insight into climate Proxy data- not strictly climatic, but provides insight into climate Tree rings, sediments, ice cores, fossil pollen, corals, and carbon ‑ 14 ( 14 C) Tree rings, sediments, ice cores, fossil pollen, corals, and carbon ‑ 14 ( 14 C)

17. Proxy Climate Records Tree Rings Tree Rings Many trees create one growth ring per year Many trees create one growth ring per year Width, density and ionic composition of the ring are indicative of climate Width, density and ionic composition of the ring are indicative of climate

18. Proxy Climate Records Ice cores have small bubbles of air Ice cores have small bubbles of air Can measure carbon dioxide and methane levels from the time the ice was created Can measure carbon dioxide and methane levels from the time the ice was created Ice Cores Ice Cores Polar ice and mountain glaciers have ice records that go back 100s or 1000s of years Polar ice and mountain glaciers have ice records that go back 100s or 1000s of years Oldest is 800,000 years Oldest is 800,000 years

19. Proxy Climate Records Sediment Sediment Biological material (ex: pollen) is deposited on the land and stored for extended periods in lake, bog, and pond sediments Biological material (ex: pollen) is deposited on the land and stored for extended periods in lake, bog, and pond sediments Pollen is useful Pollen is useful Quantity of pollen is an indicator of relative abundance of each plant species Quantity of pollen is an indicator of relative abundance of each plant species Pollen can be dated Pollen can be dated Can be used to construct a climate history Can be used to construct a climate history

20. Proxy Climate Record Coral Coral Coral exoskeleton made of calcium carbonate Coral exoskeleton made of calcium carbonate Carbonate contains isotopes of oxygen Carbonate contains isotopes of oxygen Used to determine temp of water in which the coral grew Used to determine temp of water in which the coral grew

21. Proxy Climate Record Carbon-14 and sun sunspots Carbon-14 and sun sunspots

22. Solar Cycles The Sun Goes Through Cycles The Sun Goes Through Cycles Sometimes hotter, sometimes cooler Sometimes hotter, sometimes cooler Documented by differing amounts of isotopes trapped in glacial ice Documented by differing amounts of isotopes trapped in glacial ice Variability of solar input of energy explains some of the climatic variability too Variability of solar input of energy explains some of the climatic variability too

24. We know that an increase in CO 2 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 CO 2 gas and, as a result, they release CO 2 into the atmosphere. Putting It Together

27. Feedbacks

28.  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 Consequences to the Environment Because of Global Warming

30. Potential Effects of Global Warming

31. 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. Consequences to Living Organisms

32. 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. The Controversy of Climate Change

34. 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. The Kyoto Protocol

35.  An approach involving taking CO 2 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 CO 2 from the air, from coal-burning power stations, and from other emission sources.  This captured CO 2 would be compressed and pumped into abandoned oil wells or the deep ocean. Carbon Sequestration

37. Paris Climate Conference 2015 At the Paris climate conference (COP21) in December 2015, 195 countries adopted the first-ever universal, legally binding global climate deal. The agreement sets out a global action plan to put the world on track to avoid dangerous climate change by limiting global warming to well below 2°C. The agreement is due to enter into force in 2020. Countries still have to sign it at the UN in April.