Get Fuzzy by Darby Conley

1. www.WeatherOutreach.org Get Fuzzy by Darby Conley

2. An Inconvenient Truth Discussion Lis Cohen Department of Meteorology University of Utah Lis.cohen@utah.edu www.WeatherOutreach.org

3. Summary and Comments www.WeatherOutreach.org

4. Overall Impression • Very Very well done • Climate change is a complicated topic • The science is often hard to explain • Gore did a very good job explaining the fundamentals of the science • Gore did a very good job explaining the urgency of the situation • Most of my criticisms are very nitpicky • These critiques should not substantially weaken the credibility of this movie. • The science and importance of global warming is well portrayed. • RealClimate.org (complete discussion) www.WeatherOutreach.org

5. Global Climate Change • There is no longer any scientific doubt that the Earth’s average surface temperature is increasing • 1.3°F in last century • Recent decades warmer than any comparable period in last 400 years (possibly much longer) • Ocean temperature, ice and snow cover, and sea level changes consistent with this global warming • Sea level up 7 inches in 20th century www.WeatherOutreach.org

6. Causes of Recent Climate Change • There is very high confidence that human-generated increases in greenhouse gas concentrations are responsible for most of the global warming observed during the past 50 years • It is very unlikely that natural climate variations alone, such as changes in the brightness of the sun, have produced this recent warming www.WeatherOutreach.org

7. Invasive species, disease and global warming • Invasive species due to land use change and importation • Not sure how invasive plants and insects will respond www.WeatherOutreach.org

8. Lack of cloud modeling uncertainties in the movie www.WeatherOutreach.org

9. Ice Core and CO2 • Long ice core records of CO2 and temperature in Antarctic ice cores • View 1: other climate forcings besides CO2 contribute to the change in Antarctic temperature between glacial and interglacial climate. • View 2: Gore is careful not to state what the temperature/CO2 scaling is. www.WeatherOutreach.org

10. Aerosol Concentrations in ice cores • Gore claims that you can see the aerosol concentrations in Antarctic ice cores change "in just two years", due to the U.S. Clean Air Act. • You can't see dust and aerosols at all in Antarctic cores — not with the naked eye www.WeatherOutreach.org

11. CO2 and Temperature connections in the ice core record • Observed long-term relationship between CO2 and temperature in Antarctica supports our understanding of the warming impact of increased CO2 concentrations • Moreover, our knowledge of why CO2 is changing now (fossil fuel burning) is solid. • Carbon cycle • CO2 is a greenhouse gas • Carbon cycle feedback is positive (increasing temps lead to increasing CO2 and CH4) • Future changes in CO2 will be larger than we might anticipate. www.WeatherOutreach.org

12. Climate impacts on the ocean conveyor • Timing is uncertain. • Younger Dryas 11,000 y.a. • A large discharge of fresh water into the North Atlantic disrupted currents, causing significant regional cooling. • IPCC predicts a slowdown in the circulation ~ 30% by 2100 • Circulation modeling and future inputs of melted ice -not well understood. • Few scientists are willing to completely rule out the possibility of a more substantial change in the future. www.WeatherOutreach.org

13. Ice-sheet driven sea level rise • Gore correctly asserted that melting of Greenland or the West Antarctic ice sheet would raise sea levels 20ft (6 meters). • No time frame, very uncertain • 20 ft • about how much higher sea level was around 125,000 years ago during the last inter-glacial period. • Then, global temperatures were only a degree or two warmer than today www.WeatherOutreach.org

14. Impact of sea ice retreat on Polar bears • Summer Arctic sea ice shattered all records this year for the minimum extent. • Polar bears • depend on the sea ice • hunt for seals in the spring and summer • disappearance ice • likely to impact them severely • Studying the regional populations of polar bears is not easy and assessing their prospects is tough. • Arctic ecosystems are changing on many different levels. • It may be the smaller and less photogenic elements that have the biggest impact. –RealClimate.org www.WeatherOutreach.org

15. Pacific island nations needing to evacuate • Much of Tuvalu • is only a few feet above sea level • With more sea level rise • increasing brine in groundwater • increasing damage and coastal erosion from tides and storm surges • Government of Tuvalu asked New Zealand to be ready to evacuate islanders • In the movie: "That's why the citizens of these pacific nations have all had to evacuate to New Zealand“. www.WeatherOutreach.org

16. Kilimanjaro Feb 1993 • Ongoing discussion in the literature: • Is retreat of ice on Kilimanjaro related to the direct effects of climate change? • warming atmospheric temperatures • Or indirect effects of climate change • altered patterns of humidity, cloud cover, and precipitation influencing Kilimanjaro's ice mass • Take home message • (a) ice field that we know has existed for at least the past 12,000 years is shrinking • (b) most of the other glaciers are disappearing as well. Feb 2000 www.WeatherOutreach.org http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/kilimanjaro_etm_93_00.jpg

17. Drying up of Lake Chad • Extremes • Droughts • Flooding • Lake Chad Change • reduction of rainfall across entire Sahel from 1950s to 1980s • rainfall today still substantially below high point 50 years ago • Other factors • Irrigation and upstream water use. • Substantial evidence that at least a portion of this drying out is human-caused. • Indian Ocean changes in sea surface temperature • Increase in atmospheric aerosols in the Northern hemisphere. http://www.dailymail.co.uk/pages/live/articles/news/worldnews.html?in_article_id=479576&in_page_id=1811 www.WeatherOutreach.org

18. Hurricane Katrina and global warming • Katrina is used • Destructive power of hurricanes • Cope with natural disaster • Ex. of what could get worse in a warmer world. • Nowhere does Gore state that Katrina was caused by global warming. • Individual hurricanes cannot be attributed to global warming, but the statistics of hurricanes, in particular the maximum intensities attained by storms, may be. http://geology.com/news/images/hurricane-katrina-satellite-image.jpg www.WeatherOutreach.org

19. Impact of ocean warming on coral reefs • Stress Factors • Overfishing • deliberate destruction • water pollution • sea level rise • ocean acidification • warming oceans. • That rising temperatures and other factors cause coral bleaching is true. • Bleaching episodes happen when the coral is under stress, and many examples have been linked to anomalously warm ocean temperatures http://web.syr.edu/~tjconena/coral_reefs.htm www.WeatherOutreach.org

20. Priority Actions for American Consumers • Vote! • Transportation • Choose a place to live that reduces the need to drive. • Think twice before purchasing another car. • Choose a fuel efficient, low polluting car. • Set concrete goals for reducing your travel. • Whenever practical walk, bicycle or take public transportation • Brower, 1999 www.WeatherOutreach.org

21. Priority Actions for American Consumers • Food • Eat less meat. • Buy certified organic produce. • Household Operations • Choose your home carefully. • Reduce the environmental costs of heating and hot water. • Install efficient lighting and appliances • Choose an electricity supplier offering renewable energy. • Policy • Vote, write letters, attend rallies, call your representatives and express your views. • Brower, 1999 www.WeatherOutreach.org

22. Summary • Climate Change will impact Utah in a variety of ways. • An Inconvenient Truth did a great job explaining climate change. • Most of my comments are very nitpicky • You can help slow down climate change! • Take Action Today! www.WeatherOutreach.org

23. Thank you! Lis.cohen@utah.edu www.WeatherOutreach.org www.WeatherOutreach.org

24. Background Slides www.WeatherOutreach.org

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26. Old ideas about cooling earth • The reason scientists thought the earth was cooling was because they had just discovered the milankovic cycles and saw sea core bed data that indicated we might be due for another ice age.  The didn't know about the fact that many of the components of the milancovic cycle all needed to fall in phase for the ice age to begin. • Temps decreased for about 30 years and scientists were just starting to look at climate data. • Few scientists thought this was happening with a lot of press. www.WeatherOutreach.org

27. Reference: CO2 changes during the ice ages • A full understanding of why CO2 changes in precisely the pattern that it does during ice ages is elusive, but among the most plausible explanations is that increased received solar radiation in the southern hemisphere due to changes in Earth's orbital geometry warms the southern ocean, releasing CO2 into the atmosphere, which then leads to further warming through an enhanced greenhouse effect. www.WeatherOutreach.org

28. British Judge • The judge appears to have put words in Gore's mouth that would indeed have been wrong had they been said (but they weren't). • The judge was really ruling on how "Guidance Notes" for teachers should be provided to allow for more in depth discussion of these points in the classroom. www.WeatherOutreach.org

29. Drying up of Lake Chad • Gore uses this example to illustrate that there are droughts in some regions even while other areas are flooding. • Unfortunately this is what models suggest. • The dominant cause • reduction of rainfall across entire Sahel from 1950s to 1980s • rainfall today still substantially below high point 50 years ago • Other factors • Irrigation and upstream water use. • Substantial evidence that at least a portion of this drying out is human-caused. • Recent papers (Held et al, PNAS; Chung and Ramanathan and Biasutti and Giannini) have addressed causes ranging • Indian Ocean changes in sea surface temperature • Increase in atmospheric aerosols in the Northern hemisphere. www.WeatherOutreach.org

30. Impact of sea ice retreat on Polar bears • Summer Arctic sea ice shattered all records this year for the minimum extent. • This was partially related to wind patterns favorable to ice export in the spring, but the long term trends are almost certainly related to the ongoing and dramatic warming in the Arctic. • Polar bears do indeed depend on the sea ice to hunt for seals in the spring and summer, and so a disappearance of this ice is likely to impact them severely. • The specific anecdote referred to in the movie came from observations of anomalous drownings of bears in 2004 and so was accurate. • However, studying the regional populations of polar bears is not easy and assessing their prospects is tough. • In the best observed populations such as in western Hudson Bay (Stirling and Parkinson, 2006), female polar bear weight is going down as the sea ice retreats over the last 25 years, and the FWS is considering an endangered species listing. • However, it should be stated that in most of the discussions about polar bears, they are used as a representative species. • Take home message: Arctic ecosystems are changing on many different levels. In the end, it may be the smaller and less photogenic elements that have the biggest impact. www.WeatherOutreach.org

31. Drying up of Lake Chad • Gore uses this example to illustrate that there are droughts in some regions even while other areas are flooding. • Unfortunately this is what models suggest. • The dominant cause • reduction of rainfall across entire Sahel from 1950s to 1980s • rainfall today still substantially below high point 50 years ago • Other factors • Irrigation and upstream water use. • Substantial evidence that at least a portion of this drying out is human-caused. • Indian Ocean changes in sea surface temperature • Increase in atmospheric aerosols in the Northern hemisphere. www.WeatherOutreach.org

32. Impact of ocean warming on coral reefs • Stress Factors • Overfishing • deliberate destruction • water pollution • sea level rise • ocean acidification • warming oceans. • That rising temperatures and other factors cause coral bleaching is true. • Bleaching episodes happen when the coral is under stress, and many examples have been linked to anomalously warm ocean temperatures (Australia in 1998 and 2002, all over the Indian Ocean in recent years). Corals are a sobering example of how climate change exacerbates existing vulnerabilities in eco-systems, potentially playing the role of the straw that breaks the camel's back in many instances. www.WeatherOutreach.org

33. Figure 1. Model Simulation of Trend in Hurricanes (from Knutson et al, 2004) www.WeatherOutreach.org

34. Figure 2. Measure of total power dissipated annually by tropical cyclones in the North Atlantic (the power dissipation index "PDI") compared to September tropical North Atlantic SST (from Emanuel, 2005) www.WeatherOutreach.org

35. Can giant hurricanes exist all around the world like in the Day After Tomorrow? • Clusters of thunderstorms cannot merge together to form a continent-scale blizzard with a calm eye over land. • Huge storms with calm eyes happen over the oceans not over land. • Hurricanes or Tropical Storms • Require that the core of the storm be over warm ocean water www.WeatherOutreach.org Photo: earthobservatory.nasa.gov/NaturalHazards/Arch...

36. What process could most likely change the climate? More moisture in the air Warmer climate More evaporation at the equator Circulation slows down and changes More moisture can be held in the air Water does not sink in the northern latitudes Melting Glaciers Ocean is not as salty and dense More rain at higher latitudes More freshwater in the ocean www.WeatherOutreach.org

37. Three Glaciers Retreating • Source: C.L. Andrews. 1912, 1938. Denver Glacier: From the Glacier Photograph Collection . Boulder, CO: National Snow and Ice Data Center. Digital Media; Marion T. Millett. 1958. Denver Glacier: From the Glacier Photograph Collection . Boulder, CO: National Snow and Ice Data Center. Digital Media. www.WeatherOutreach.org

38. Temperature and Ice Accumulation vs. Time www.WeatherOutreach.org

39. Data Sources • The 2007 IPCC (Intergovernmental Panel on Climate Change) report • Includes • 2,500 + scientific expert reviewers • 800+ contributing authors • 450+ lead authors from • 130+ different countries • 6 years of work • 4 volumes • 1 report • Scientific Literature • Presentations from experts at the University of Utah – Dr. Dave Chapman, Dr. Tim Garrett, Dr. Gerald Mace, Dr. Thomas Reichler www.WeatherOutreach.org

40. Temperature Analysis • “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level” (IPCC report 2007). www.WeatherOutreach.org

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43. Contributions to Sea Level Rise www.WeatherOutreach.org

44. Long-term Changes in Climate • Long-term changes are observed at: • Continental Scales • Regional Scales • Ocean basin Scales • These changes include: • Changes in Arctic temperatures and ice • Widespread changes in precipitation amounts • Ocean salinity • Wind patterns • Aspects of extreme weather • Droughts • Heavy precipitation • Heat waves • Intensity of tropical cyclones - 2007 IPCC report www.WeatherOutreach.org

45. What can change our climate? • Changes in these factors alter the energy balance of the climate system: • Solar radiation • Land surface properties • The atmospheric abundance of greenhouse gases and aerosols -2007 IPCC Report www.WeatherOutreach.org

46. The Greenhouse Effect www.WeatherOutreach.org

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48. How are greenhouse gas impacts measured? • These impacts are expressed in terms of radiative forcing, which is used to compare how a range of human and natural factors drive warming or cooling influences on global climate. www.WeatherOutreach.org

49. LOSU = level of understanding RF = Radiative Forcing Error bars Additional forcing factors not included here are considered to have a very low level of scientific understand. www.WeatherOutreach.org

50. How is the sun affecting climate change? The effect of the sun’s variations accounts for +.12 W/m2. There is very high confidence that the globally averaged net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6 [+0.6 to +2.4] W/m2. Natural Climate Variability because of the sun has been not very significant. www.WeatherOutreach.org