Global Warming over the Pacific Northwest: Separating Fact from Hype

1. Global Warming over the Pacific Northwest: Separating Fact from Hype Cliff Mass, University of Washington

2. There is a great deal of contradictory information about global warming, including its influence on the Northwest

3. Some environment groups have proposed that global warming has already caused our precipitation to become more extreme

4. Seattle’s Mayor and others suggested our snowpack had declined by 50%

5. And media headlines have become more and more scary

6. In contrast, others hold that the lack of warming of the planet over the past decade indicates that global warming is no real threat ..or that the earth is cooling ill

9. Some ask: How can scientists predict climate when they can’t get the next week’s weather forecast right?

10. …while thousands of scientists from around the world have written a series of reports indicating the imminent threat of global warming due to mankind’s influence

11. Intergovernmental Panel on Climate Change (IPCC) Reports

12. The Global Warming Debate Has Divided Into Tribal Warfare

13. What is the truth? What is biased and wrong? What do we know for sure? What are the uncertainties? What will happen here? What needs to be done?

14. The Problem:greenhouse gases are increasing

15. Greenhouse Gases Warm the Earth • Carbon Dioxide • Water Vapor • Methane • Nitrous Oxide • … and others

16. We understand the greenhouse effect Graphic courtesy of the National Park Service

17. Svante Arrhenius, 1896

18. The Atmosphere is Like a BlanketMore Blankets Result in More Warming—The Question is: How Much?

19. We Can Predict the Future Effects of More Greenhouse Gases Using Climate Models • Sophisticated computer simulations based on the physics of the atmosphere. • Nearly identical to weather prediction models, which are tested every day, but atmospheric gases can vary. • These models are very good, but are not perfect

20. Climate Model Output for 2100

21. Global Warming is NOT Uniform • Arctic warms up the most for a number of reasons, including the melting of sea ice. • Continents warm up more than oceans. • Eastern oceans up less than western oceans. • In general, the drier areas (e.g., the SW) will get drier and wet areas (e.g., British Columbia) will get wetter.

22. Uncertainty: Get Used to It! • Considerable uncertainty regarding global temperature changes (roughly 1.5 to 4 C) • Even more uncertainty for local changes • Uncertainty has not lessened over the past decades of research.

23. Global Warming in Northwest • It appears that there has been little human-caused warming in most of the Northwest so far. • This makes a lot of sense--our weather has controlled by the Pacific and the eastern Pacific is one of the last places that will warm significantly. • Global warming will be weaker and delayed here…but it will happen in force by the end of the century.

24. Change in Winter Surface Air Temperature (°C) for 1979-2008 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 +0.2 +0.4 +0.6 +0.8 +1.0 +1.2 +1.4 Air Temperature Trend (1979-2005)

25. Little trend in Cascade snowpack over the last 30 years

26. Globally warming will become highly significant in our region by the end of the centuryLet’s look at some projections using a high-resolution forecast model driven by global climate simulations

27. Change in Winter Surface Air Temperatures (F)

31. Change in Snowpack from 1990 to 2090 -40% 0% +40%

33. Don’t buy this after 2050!

34. But Good News for Precipitation! Unlike some areas, we will still have plenty of precipitation, just more rain and less snow

35. Annual precipitation change over the next century

36. Big Questions

37. Can We Predict Climate When We Can’t Forecast Next Week’s Weather?

39. In weather prediction we forecast the exact state of the atmosphere at some time in the future • Tomorrow’s high in Spokane will be 67F • It will rain tomorrow afternoon after 3 PM

40. In Climate Prediction We DON’T Do This. • We predict average quantities over extended periods. • Example: the mean winter temperatures will be 3F higher over the Pacific Northwest. • MUCH easier to do. • Furthermore, the average conditions are closely controlled by the amount of radiation reaching and leaving the planet--and we can figure that out fairly well—IF WE KNOW THE ATMOSPHERIC COMPOSITON.

41. Should we expect stronger storms and more floods under global warming in the NW?

42. We don’t know.

43. The number of windstorms and floods have increased during the past decade or so in Washington, but DECREASED in Oregon and northern CA. • Storms follow the jet stream --a current of strong winds in the upper atmosphere--and most climate models predict the jet stream will move northward. • It is possible that storms here might move north of us under global warming.

44. Extreme Craziness • Greenhouse warming “advocacy” groups and some activist scientists have been making unfounded claims that individual extreme weather events are undoubtedly the effects of global warming. • The media highlight such reports as if they were true. • Many are not.

47. Texas TemperaturesNo Real Trend

48. Are We Making Any Real Progress in Dealing with Global Warming?

49. The Answer is Clearly No

50. The U.S. is reducing carbon emissions, while China and others take off