1Last Lecture“We do not inherit the earth from our ancestors, we borrow it from out children.”Native American ProverbTsunamisThe world was stunned on December 26, 2004 when the powerful Sumatra- Andaman earthquake triggered tsunamis that demolished many coastal areas of South and Southeast Asia.No.Are Tsunamis caused by global warming?What would have to happen to get a 5 meter rise in global sea levels?A) Just mountain glacier meltB) Just sea ice meltC) About 10% of Greenland Ice SheetD) Almost Entire Greenland Ice SheetE) Almost Entire Antarctica Ice Sheet2Recent scientific publications from models indicate this is not a likely scenario.Was hurricane Katrina caused by global warming?Are hurricanes statistically more likely to occur and more likely to be more powerful with warmer oceans?What is the difference between these two answers?Note that the next hurricane season was predicted to be bad, but was quite mild. Does this disprove global warming?Key PointsWhat is solid scientific consensus?What is speculative?When does one point prove or disprove everything by itself?Notice that most of the points are important, but not to the overall picture…1. Judge Burton found that Gore's assertion of a rapid rise in sea-levels caused by the melting of icecaps in Antarctica was overly "alarmist."2. Gore claimed that the disappearance of year-round snow from the summit of Mount Kilimanjaro in Africa was expressly attributable to global warming. The court was not convinced. According to Burton, the scientific "consensus" is that the reasons for the snow recession on Kilimanjaro cannot be established. 3. Gore cited a scientific study showing that polar bears had drowned by "swimming long distances--up to 60 miles--to find the ice." Evidence backing up this claim was not produced to the British court. 4. Gore attributed the Hurricane Katrina devastation to global warming. The judge found that there was "insufficient evidence to show that." 5. The Gore movie depicted the drying up of Lake Chad as a prime example of the effects of global warming. Expert testimony in front of the British court suggested that "far more likely causes" were "population increase, over-grazing, and regional climate variability." 6. Gore suggested an "exact fit" between the rise in carbon dioxide levels and the rise in temperatures over a period of 650,000 years. According to the judge, scientists generally agree that there is "a connection," between the two phenomena, but claims of an "exact fit" cannot be established.37. An "Inconvenient Truth" claimed that citizens of some low-lying inhabited Pacific atolls "have all had to evacuate to New Zealand" because of the inundation of their islands caused by global warming. The judge said that he found no evidence of "any such evacuation having yet happened." 8. The movie suggested that global warming could shut down "the Ocean Conveyer," a process by which the Gulf Stream is carried over the North Atlantic to Western Europe. The judge cited a study by the Intergovernmental Panel on Climate Change (IPCC), the co-winner of the Nobel Peace prize, which concluded that it was "very unlikely" that the Ocean Conveyer would be shut down completely, although it might slow down.9. Gore argued that coral reefs all over the world were bleaching because of global warming and other factors. The judge cited the IPCC view that it was difficult to separate the impact of stresses on coral reefs caused by climate change "from other stresses such as over-fishing and pollution."* Note that they did approve showing the movie in Great Britain public schools with the above caveats.What do you think?A) It disproves global warming.B) It is irrelevant since the British judge is not a scientistC) It shows that some points are pushed too farD) It is appropriate to push points to get people’s attentionE) The movie and Al Gore do a great serviceI personally and scientifically believe (C) and (E), though mostly (E).What can we or should we do about it?One item to realize is that our planet is never static. It is a constantly changing environment. Ice ages are more often the norm.There have also been far distant times when all the polar ice was melted.The entire history of human civilization…Changes in earth’s orbit (perturbations from other planets), changes in the tilt axis, etc. all have impacts on global climate.The earth will eventually enter another ice age.4So why is this different?Much more rapid time scale !Human population near or well above carrying capacity.Some estimates are that planet can support 2 billion people at USA standard of living.Atmospheric CO2(input) Temperature (output)CCSM Future: Next 100+ yearsLow Clouds Over the OceanOther Observables….What do you notice between these two models?A) ConsistentB) DifferentC) Disproves global warming modelsKyoto ProtocolMeeting in December, 1997Developed countries:Reduce greenhouse gases by 5% from 1990 levelsUS reduction about 7% from 1990 levelDeveloping countries:No limit ! Æ including ChinaRatified by 141 countries by 2005 (not including the USA)51) Replace five incandescent lightbulbs in your home with compact fluorescents: Swapping those 75-watt incandescents with 19-watt CFLs can cut 275 pounds of CO2.2) Instead of short haul flights of 500 miles or so, take the train and bypass 310 pounds of CO2.3) Sure it may be hot, but get a fan, set your thermostat to 75 degrees and blow away 363 pounds of CO2.4) Replace refrigerators more than 10 years old with today's more energy-efficient Energy Star models and save more than 500 pounds of CO2.5) Shave your eight-minute shower to five minutes for a savings of 513 pounds.6) Caulk, weatherstrip and insulate your home. If you rely on natural gas heating, you'll stop 639 pounds of CO2 from entering the atmosphere (472 pounds for electric heating). And this summer, you'll save 226 pounds from AC use.How to be more GreenHow to be more Green……(NPR.ORG list)(NPR.ORG list)7) Whenever possible, dry your clothes on a line outside or a rack indoors. If you air dry half your loads, you'll dispense with 723 pounds of CO2.8) Trim down on the red meat. Since it takes more fossil fuels to produce red meat than fish, eggs and poultry, switching to these foods will slim your CO2 emissions by 950 pounds.9) Leave the car at home and take public transportation to work. Taking the average U.S. commute of twelve miles by light rail will leave you 1,366 pounds of CO2 lighter than
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