Global Warming 101

1. Global Warming 101

2. The Earth With No Atmosphere (infrared) Earth’s surface would be 60F cooler than today…no life.

3. But the Earth has an atmosphere! • Includes gases such as nitrogen and oxygen • Also includes greenhouse gases.

4. What is a Greenhouse Gas? • Greenhouse gas is a gas that that is relatively transparent to solar radiation, but absorbers and emits in the infrared…the type of radiation the earth emits. • Some examples: • Water vapor • Carbon dioxide • Nitrous oxide • Methane

5. Earth With An Atmosphere That Includes Greenhouse Gases Partly (infrared) Greenhouse Gases Make the Earth Warmer by Slowing the Loss of Infrared Radiation

6. Greenhouse Gases Warm the Earth in a Similar Way That Blankets Warm Us at Night

7. The Problem: Rapidly Rising Greenhouse Gases Due to Mankind

10. Gases Trapped in Ice Gives Us a History of the Gases in the Atmosphere

11. But it is worse than that… • There are a number of natural “amplifiers” of mankind’s emission of greenhouse gases. • The warming due to increased carbon dioxide, methane, and other greenhouse gases will cause more water to be evaporated from the earth’s oceans.

12. Why? • The amount of evaporation increases with temperature. • Water vapor is the most potent greenhouse gas and thus causes even MORE warming. • This is caused a positive feedback.

13. But it gets even worse… • Warming temperatures melt snow and ice. • Snow and ice help cool the planet because they reflect much of the sun’s radiation….that is why you need sun glasses while skiing. • As the snow, melts less radiation is reflected to space and more is absorbed. • Thus, the earth gets warmer, which melts more snow. • Another positive feedback!

15. Is Global Warming Already Happening? • Finding the global warming signal is made more difficult because the earth’s climate has a certain amount of natural variability. • Also the warming due to man was relatively small before the middle of last century before the large increase in fossil fuel usage. • The consensus of most atmospheric scientists is that some global warming signal due to man is now evident.

17. Eleven of the twelve warmest years in the past 150 years have occurred in the past twelve years (1995-2006)

18. These photographs, taken in 1928 and 2000, show how South Cascade Glacier in the Washington Cascade Mountains has retreated over time.

19. But what about the future?

20. The Technology of Prediction • Atmospheric scientists use complex climate prediction models…called General Circulation Models…to predict the future climate. • These models are similar to weather forecast models, but allow the gases in the atmosphere to change. • They also simulate the evolution of the oceans. • Have to assume the future emission of greenhouse gases by mankind…a major uncertainty. • These models are not perfect and cannot exactly replicate the current climate….but they are close and getting better each year.

21. Details on Current Study: GCM • Which Scenario Will Mankind Follow? IPCC Report, 2001 IPCC Report, 2001

22. IPCC.AR4.2007

24. Sample Climate Model Output for 2100

25. Projections of Future Changes in Climate Projected warming in 21st century expected to be greatest over land and at most high northern latitudes and least over the Southern Ocean and parts of the North Atlantic Ocean

26. What about the Northwest • Several of us are applying very high resolution simulations forced by the global climate model predictions • Gives a view of the local implications of global warming. • Could our mountains and other local features make it worse or better?

32. Large Drop in Snowpack in the Mountains

33. Key Facts • The overwhelming majority of atmospheric scientists believe global warming has occurred and will became MUCH larger during the next decade. • This is based on the best technology and observations available. • There are substantial uncertainties, so we can’t give a specific number, but a range. • Even if increases in the emission of greenhouse gases stop today, a certain amount of global warming is inevitable.

34. Range of Global Warming

35. Global Warming Goes Politicaland Reaches the Public Arena

36. Inconvenient Truth: Basically Accurate But Contains a Few Errors

37. Downplays Global Warming:Full of Major Errors

38. The Day After Tomorrow: Global Warming Causes Ice Age: Complete Nonsense

39. Mayor Nickels and Global Warming • Claims of a 50% reduction in Cascade snowpack due to global warming are simply not true. • Perhaps 10-15%

40. With a lack of Federal response, States are beginning to push significant responses to global warming.

41. Bottom Line • Global warming and its local implications are extraordinarily serious. • There are significant uncertainties, but they are NOT in whether global warming will occur, but rather the magnitude and its local effects. • With the large current population of the planet, we lack a margin of safety. • There is much the world can do to lessen greenhouse gas emissions (e.g., better fuel mileage on cars, new transportation technologies, new energy technologies, etc)

42. The Torah Example • Joseph foresaw a major shift in climate…not unlike modern scientists. • He was able to get the attention of the powers that be…the Pharoah… convincing him of the threat and providing a plan of action. • Joseph managed the plan and saved Egypt, Israel, and other nations. • Can we show similar foresight and active response today?

43. The End