1. Climate and Climate Change

2. Climate is what you expect and weather is what you get

3. Green Bay 1977-2002

4. Green Bay 1887-2002

7. Long-Term Trends

12. Some Conclusions This is not as easy as the media make it seem The fact that it’s not easy doesn’t excuse us from dealing with it The fact that something can’t be proven conclusively doesn’t protect you if you make the wrong decision Don’t confuse reasoning with reality

13. Greenhouse Effect

14. Negative Greenhouse Effect

15. Positive and Negative Greenhouse Effects Positive Greenhouse Effect Light enters IR trapped: Warming Negative Greenhouse Effect Light Blocked IR can leave: Cooling Titan

16. Greenhouse Gases Water Vapor Carbon Dioxide Methane Nitrous and Nitric Oxides Ozone Transparent to visible light but absorb infrared

17. What Color is Water?

18. Infrared Absorption

19. Carbon Dioxide Has doubled to 350 ppm since start of Industrial Revolution Coupled to Temperature Rise? More Cloud Cover? Taken up by biomass? Taken up by oceans?

20. Paleoclimatology The present is the key to the past – but The past is also the key to the present Study of ancient climates Have to rely on proxy measurements How to convert qualitative data to numbers?

21. Ancient Paleoclimatology Oxygen 18 Fossils Evaporites Glacial Indicators Air bubbles in amber

22. Earth’s Climatic History Faint Early Sun Anoxic Atmosphere Advent of Life – UV Protection? 2.3 by Glaciation 2 b.y. Oxygen Threshold End of Iron Formations First Red Sandstones Snowball Earth

23. Earth’s Climatic History Cambrian Explosion Ordovician Ice Age Advent of Forests Permian Ice Age Cretaceous Warm Period Eocene Warm Period Pleistocene Ice Age

24. Recent Paleoclimatology Historic Records Tree Rings Pollen Studies Oxygen 18 Ice Cores

25. Holocene Climate 11,000 Younger Dryas Cooling 9,000-6,000 Mid-Holocene Warm Period (“Climatic Optimum”) 900-1300 AD – Medieval Warm Period 1300-1450 Little Ice Age I 1450-1550 Recovery 1550-1800 Little Ice Age II

26. Effects of Global Warming More Heat Extremes Drought Rise in Sea Level Temporary Severe Cold Spell? Rapid Migration of Ecological Zones More Biomass but Lower Nutritional Value

27. Not a Bad Thing? Reduced Energy Demands Longer Growing Seasons More Biomass More Habitable Land

28. Ozone Stratosphere – Good Absorbs solar ultraviolet Troposphere – Bad Toxic Contributes to air pollution

29. Ozone Depletion Cl stripped off synthetic molecules by solar ultraviolet Cl reacts with ozone, acts as catalyst Cl – CF3 (Freon) 360 Cl – CCl3 (Carbon tetrachloride) 294 Cl – H(Hydrochloric Acid)431

30. Smog

31. Particulate Matter

32. Long-Term Climatic Trends Brightening of the Sun Capturing of CO2 by carbonate rocks? Moist greenhouse effect Runaway CO2 Greenhouse Effect Venus conditions

33. The Goldilocks Problem Venus is too hot Mars is too cold Earth is Just Right

34. Planetary Habitable Zones Primarily in the Liquid Water Zone Can’t be too warm Water Vapor in upper atmosphere broken down by solar UV and charged particles (photodissociation) Hydrogen escapes to space

35. The Ultimate Long-Term Forecast Slow warming trend for the next billion years Increasing humidity CO 2 decrease leads to extinction of plants? Boiling and evaporation of the oceans

36. Planetary Habitable Zones

37. The Oreo Model of Life History Micro-organism Earth (0-3 billion years) Multicellular Earth (3-5 billion years) Micro-organism Earth (5-6 billion years) “The white creamy middle”