1. Climate Change and Severe/Hazardous Weather

2. Now impossible to refute warming… On the left is a photograph of Muir Glacier taken on August 13, 1941, by glaciologist William O. Field; on the right, a photograph taken from the same vantage on August 31, 2004, by geologist Bruce F. Molnia of the United States Geological Survey (USGS). On the left is a photograph of Muir Glacier taken on August 13, 1941, by glaciologist William O. Field; on the right, a photograph taken from the same vantage on August 31, 2004, by geologist Bruce F. Molnia of the United States Geological Survey (USGS).

3. Ice Free Summer Arctic?

4. But is it anthropogenic?

6. If only it were just the greenhouse gases

10. From Emanuel, 2007 © 2007, Massachusetts Institute of Technology

11. Check the Pulse from the CPC http://www.climate.gov/#climateWat ch http://www.climate.gov/#climateWat ch http://www.climate.gov/#climateWat ch http://www.climate.gov/#climateWat ch

12. What We Know For Sure Greenhouse gases are increasing due to fossil- fuel and biomass burning Greenhouse gases are increasing due to fossil- fuel and biomass burning 280 to 380 ppm since pre-industrial, up 35%. Highest in 650,000 years at least.280 to 380 ppm since pre-industrial, up 35%. Highest in 650,000 years at least. Aerosols increasing due to industrial activity. Aerosols increasing due to industrial activity. Earth’s Temp up 1.2°F in past century, mostly in 1920 to 1950 and then starting in 1975. Earth’s Temp up 1.2°F in past century, mostly in 1920 to 1950 and then starting in 1975. Sea Level up 2.7 inches in past 40 years, an inch in the last 10. Sea Level up 2.7 inches in past 40 years, an inch in the last 10. Arctic Sea Ice decreased by 15-20% since 1978. Arctic Sea Ice decreased by 15-20% since 1978.

13. What we are fairly certain about Global temp now highest in at least 500-1000 years Global temp now highest in at least 500-1000 years Global temp variability due to four factors: Global temp variability due to four factors: Variability of solar outputVariability of solar output Volcanic eruptionsVolcanic eruptions Anthropogenic Sulfate AerosolsAnthropogenic Sulfate Aerosols Greenhouse gasesGreenhouse gases Last 30 year dramatic warming due to greenhouse gases Last 30 year dramatic warming due to greenhouse gases Without controlling greenhouse gas emissions, global temp will rise 2.5 to 9°F over the next century Without controlling greenhouse gas emissions, global temp will rise 2.5 to 9°F over the next century

14. More debate involved: impacts 6 to 16 inches of sea level rise in next century, unless … 6 to 16 inches of sea level rise in next century, unless … Greenland goes – ouch - 20 feet!Greenland goes – ouch - 20 feet! Rainfall in concentrated events Rainfall in concentrated events Drought and Flood increase Drought and Flood increase Hurricanes Hurricanes More Powerful (already see)More Powerful (already see) Maybe less frequentMaybe less frequent

15. Less wintertime T Contrast: PFJ weaker and farther north PFJ weaker and farther north Continental ET Lows less frequent and intense, may move more slowly Continental ET Lows less frequent and intense, may move more slowly There goes the chase…There goes the chase… Gulf E/Coast lows maybe less frequent, but stronger due to stronger SSTs, reduced stability Gulf E/Coast lows maybe less frequent, but stronger due to stronger SSTs, reduced stability Supercells – less shear, may mean less, but Thunderstorms in general unsure Supercells – less shear, may mean less, but Thunderstorms in general unsure

16. Patterns shifting Some poleward, of course Some poleward, of course More atmospheric water vapor More atmospheric water vapor More intense rain events More intense rain events Flooding in generalFlooding in general More winter rain events (vice snow) – more winter floodingMore winter rain events (vice snow) – more winter flooding Other human activity exacerbates (more concrete, stream intervention, etc.)Other human activity exacerbates (more concrete, stream intervention, etc.) SW U.S.: Drier (already started) SW U.S.: Drier (already started) Plains: Lowering water table Plains: Lowering water table European production Area also drier European production Area also drier Global Food Supply issueGlobal Food Supply issue Another compounding water problem – less storage in snowpack Another compounding water problem – less storage in snowpack

17. More Impacts El Niño: A wildcard. Could have an average state more like an El Niño year. El Niño: A wildcard. Could have an average state more like an El Niño year. More and Stronger Heat Waves…duh… More and Stronger Heat Waves…duh…

18. In the Unlikely Event all of the experts are wrong… (Or, if some unforeseen mechanism of our benevolent planet kicks in…) Most of what we need to do – shouldn’t we be doing anyway?

19. OMG Scenarios Methane Clathrates in Continental Shelf Methane Clathrates in Continental Shelf Peat Bogs of the Tundra Peat Bogs of the Tundra Greenland Greenland ?