1. 21.7 Greenhouse Effect: the carbon cycle and global warming Consequences of global warming Increased temperatures tend to decrease plant productivity Parasites and other plant ailment become more prevalent during higher temperatures Precipitation and soil moisture effects In a warmer world, precipitation and evaporation should increase

2. 21.7 Greenhouse Effect: the carbon cycle and global warming Extreme weather events models indicate more and worse Data shows this prediction proving out Changes in biodiversity in some latitudes, 70% of habitats will be affected Sensitive or specialist species could die off E.g.: polar bears are endangered due to lack of pack ice 3. 21.7 Greenhouse Effect: the carbon cycle and global warming Sea-level changes sea-level has risen markedly from 1900 to 2000 water expands when warm Glacial melting is increasing Effects on people Tropical diseases flaring up in new areas Population stress on food and water supplies as well as other global systems 4. Fig. 21.17, p.546 5. 21.8 Feedback and threshold mechanisms in climate change Many Earth systems exhibit non-linear responses to change Albedo effects melting ice decreases albedo through loss of white and changes in vegetation. What snows are left are blocked by brushy growth Imbalances in rates of plant respiration and photosynthesis. Decay respiration increases when warmer, releasing more CO2 which makes it warmer. 6. Fig. 21.18, p.548 7. 21.8 Feedback and threshold mechanisms in climate change West Antarctic ice shelf has collapsed in sections. Grounded ice is thinning and lifting in others, and floating ice is breaking up. As ice floats, seawater creeps beneath causing glacial movement to increase. Break-up of the West Antarctic Ice Sheet will raise sea level 8. Fig. 21.19, p.549 9. 21.8 Feedback and threshold mechanisms in climate change Thermohaline circulation how global warming could cause global cooling Warmer sea surface temperature could slow or stop vertical currents This would stop, or re-route the Gulf Stream, which would cool the Earth Thermohaline currents have decreased 30% from 1988 - 2000 10. Fig. 21.20, p.550 11. Fig. 21.16, p.544 12. Consequences of Global Climate Change These two websites contain videos discussing the consequences of climate change. The National Geographic is a short 8 minute video. The rockhopper is a series of 1 hour videos produced by BBC. http://www.rockhopper.tv/search?form=sea rch&q_widget=hot+cities&submit=Search http://video.nationalgeographic.com/video/ player/environment/global-warming- environment/way-forward-climate.html 13. 21.9 The Kyoto treaty on greenhouse warming Dec. 1997, 160 nations met to discuss global warming By Feb. 2005 a treaty was ratified by many of them Creates a global trading market for CO2 emissions Sets limits and goals to enact Caps and goals tied to nations economies 14. 21.9 The Kyoto treaty on greenhouse warming The U.S. has never ratified the treaty Treaty supporters argue: Wealth not necessarily tied to fuel consumption Curbing consumption and emissions could help the economy Models show the longer we wait, the worse it will get Consider the alternatives: runaway temperature changes, famine, global unrest. The treaty expires in 2012 the sequel is looking less than inspired. 15. Fig. 21.21, p.551 16. Whats next ??? The Durban Conference held in 2011 attempts to develop the follow on protocol to the Kyoto treaty. Discussions continue from that forum to establish the next steps in addressing climate change. http://unfccc.int/meetings/durban_nov_2011 /meeting/6245.php