Climate and Climate Change

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

5. Green Bay 1887-2002

6. Green Bay 1887-2002

7. Long-Term Trends

8. Long-Term Trends

9. Long-Term Trends

10. Long-Term Trends

11. 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 • CO2 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”