Human and Natural Influences on the Environment: Who’s Doing What?

1. Human and Natural Influences on the Environment: Who’s Doing What? Rick Ulrich Dept. of Chemical Engineering Univ. of Arkansas rulrich@uark.edu Feb. 22, 2006

2. We’re very concerned these days about climate change caused by human activity. Are our actions affecting it?

3. Human and Natural Influences on the Environment: Who’s Doing What? How has the Earth’s climate changed before people? • Temperature through history • How does the last 150 years compare to before? • We’re in a lucky time! Greenhouse gases • Guilty of that much, anyway Who’s Doing What? • Things we can agree on Brave political prediction

4. Average Temperature on Earth Through the Ages How do we know this? • Thermometer records, since ~1800 • Historical records, since ~300 BC • Tree rings, thousands of years • Isotopic analysis in soil, ice, preserved biological material, millions of years Oxygen 16 vs. Oxygen 18 • water contains both, but mostly 16 • the ratio of 16O to 18O in ice gives T when evaporated and precipitated The avg T on Earth now is 15°C = 59°F

5. Analysis of Ice Cores from Siberia

6. 2005 WW-II WW-I

7. 2005

8. 8,000 BC Glaciers leave continental U.S. 1.0 10,000 BC Land bridge from Siberia to Alaska sinks 6,500 BC English Channel forms Medieval Warm Period 0.5 2005 0 DT from 2005 (°C) Sea level rises ~400 ft -0.5 -1.0 Little Ice Age -1.5 2000 BC 10,000 BC 8000 BC 6000 BC 4000 BC 0 2000

9. 2005 0 -2 -4 DT from 2005 (°C) -6 -8 -10 Neanderthals Homo Erectus 400 350 300 250 200 150 100 50 0 Thousands of Years Ago

10. 2005 DT from 2005 (°C) “Lucy” 40 ice ages 11 ice ages 5.0 4.0 3.0 2.0 1.0 0 Millions of Years Ago

11. Paleocene-Eocene Thermal Maximum 20 dinosaurs R.I.P. 10 Approx. DT from 2005 (°C) 2005 0 split! evolution of primates -10 60 50 40 30 20 10 0 Millions of Years Ago

12. Dinos R.I.P. Cambrian Explosion land animals insects first fish reptiles + amphibians dinosaurs 6-8°C (11-14°F) warmer than today Hotter Colder no polar ice 2005 Ice Ages Ice Ages Ice Ages 0 500 400 300 200 100 Millions of Years Ago

13. Earth solidifies, oceans condense photosynthesis multi-cell organisms Cambrian Explosion Earth forms oxygen rises in atmosphere earliest life: bacteria Exact temperatures = ??? Earth probably never completely frozen and probably never much warmer than ~35C (95°F). CO2 levels may have been as high as 10% 2005 Ice Ages 0 1 2 3 4 Billions of Years Ago

15. 0 2005 -2 -4 DT from 2005 (°C) -6 -8 -10 Neanderthals Homo Erectus 400 350 300 250 200 150 100 50 0 Thousands of Years Ago

16. Interglacials 0 2005 Ice Age Ice Age Ice Age Ice Age -2 -4 DT from 2005 (°C) -6 -8 -10 Neanderthals Homo Erectus 400 350 300 250 200 150 100 50 0 Thousands of Years Ago

17. 100,000 years cold then 10,000 years warm warm, ice retreats warm, ice retreats warm, ice retreats warm, ice retreats warm, ice retreats 0 2005 -2 -4 DT from 2005 (°C) -6 -8 -10 Neanderthals Homo Erectus 400 350 300 250 200 150 100 50 0 Thousands of Years Ago Long descent to colder temps, along with progressively more severe advances of ice. Rapid warming to interglacial periods, maybe fast as 1000 years.

18. Recent Ice Ages are Caused by Astronomical Effects 2005 DT from 2005 (°C) “Lucy” 40 ice ages 11 ice ages 5.0 4.0 3.0 2.0 1.0 0 Millions of Years Ago Matches cycle of Earth’s orbital shape Matches cycle of Earth’s tilt

19. We’re perched on top of a relatively short interglacial period. 0 2005 -2 -4 DT from 2005 (°C) -6 -8 -10 Neanderthals Homo Erectus 400 350 300 250 200 150 100 50 0 Thousands of Years Ago

20. A Quick Review Greenhouse Gases • Our atmosphere is transparent to visible sunlight • Sunlight hits, and heats, the ground • Ground radiates IR up, but greenhouse gases trap IR • Greenhouse gases absorb IR, releasing it as heat Nitrogen 77% Oxygen 21% Water Vapor 0 - 4% Carbon Dioxide 0.035% Methane 0.00015%

21. A Quick Review Greenhouse Gases • Our atmosphere is transparent to visible sunlight • Sunlight hits, and heats, the ground • Ground radiates IR up, but greenhouse gases trap IR • Greenhouse gases absorb IR, releasing it as heat Nitrogen 77% Oxygen 21% Water Vapor 0 - 4% Carbon Dioxide 0.035% Methane 0.00015% Does not absorb IR, Not greenhouse gases Absorbs IR, Greenhouse gases

22. Greenhouse Gas Induced Warming Makes You Possible If not for global heating caused by greenhouse gases: • Earth’s avg temperature would be -18°C (0°F) • The oceans would freeze solid to km depths • No rain, no rivers • Venus would be 70°C (160°F) and could have water Earth gets +33°C (60°F) from present CO2, CH4, H2O

23. Humans really are responsible for the rise of greenhouse gases over the past two centuries. “Anthropogenic” = caused by humans

24. Do these curves match?

25. What About All Those Doomsday Predictions? Species wiped outCountries underwaterKiller hurricanes Mass starvationWorldwide deserts Collapse of food chain Tsunamis! These make for better press than more measured predictions

26. CNN, Feb 8: “U.S. Had Warmest January on Record” At least since records have been kept - 1895 Beat out 1953 8.5°F warmer than the average January We know “exactly” why:

27. CNN, Feb 8: “U.S. Had Warmest January on Record” At least since records have been kept - 1895 Beat out 1953 8.5°F warmer than the average January We know “exactly” why: the jet stream stayed to the north North of the jet stream, temperatures were below average Then, new York City had its largest snowfall on record the next month!

28. Here’s another climate-related news item: “There are ominous signs that the Earth’s weather patterns have begun to change dramatically and that these changes may portend a drastic decline in food production– with serious political implications for just about every nation on Earth. The drop in food output could begin quite soon,perhaps only 10 years from now. The regions destined to feel its impact are the great wheat-producing lands of Canada and the U.S.S.R. in the North, along with a number of marginally self-sufficient tropical areas . . .”

29. The Cooling World Newsweek, April 1975 “There are ominous signs that the Earth’s weather patterns have begun to change dramatically and that these changes may portend a drastic decline in food production– with serious political implications for just about every nation on Earth. The drop in food output could begin quite soon, perhaps only 10 years from now. The regions destined to feel its impact are the great wheat-producing lands of Canada and the U.S.S.R. in the North, along with a number of marginally self-sufficient tropical areas . . .”

30. 1975 WW-II WW-I

31. Hurricane History WW-I WW-II Named Storms All Hurricanes Cat 3 or Higher Hurricanes

32. 0.30 0.20 Sea Level Change (m) 0.10 0

33. 0.30 0.20 Sea Level Change (m) 0.10 If all ice on Earth melted +75 m (+230 ft) Would take 38,000 yrs at present rate 0

34. CO2 and T have been tracking each other long before we could have had any effect on the climate. T rise = 0.8°C since 1850 last ice age 2005 temperature 0 DT (°C) -5 natural fluctuation -10 2005 CO2 360 anthropogenic since 1850, up 29% 300 natural fluctuation 200 ppm CO2 100 0 400 350 300 250 200 150 100 50 0 Thousands of Years Ago

35. These Things Are True For Sure • The Earth’s climate has always fluctuated on its own over a very wide range of temperatures. For most of its history, the climate has been much warmer than it is today.

36. These Things Are True For Sure • The Earth’s climate has always fluctuated on its own over a very wide range of temperatures. For most of its history, the climate has been much warmer than it is today. • The concentration of greenhouse gases in the atmosphere also fluctuates naturally over a wide range.

37. These Things Are True For Sure • The Earth’s climate has always fluctuated on its own over a very wide range of temperatures. For most of its history, the climate has been much warmer than it is today. • The concentration of greenhouse gases in the atmosphere also fluctuates naturally over a wide range. • Humans are increasing the concentration of greenhouse gases.

38. These Things Are True For Sure • The Earth’s climate has always fluctuated on its own over a very wide range of temperatures. For most of its history, the climate has been much warmer than it is today. • The concentration of greenhouse gases in the atmosphere also fluctuates naturally over a wide range. • Humans are increasing the concentration of greenhouse gases. • Greenhouse gases cause upward pressure on global temperatures, but the actual extent is not known.

39. These Things Are True For Sure • The Earth’s climate has always fluctuated on its own over a very wide range of temperatures. For most of its history, the climate has been much warmer than it is today. • The concentration of greenhouse gases in the atmosphere also fluctuates naturally over a wide range. • Humans are increasing the concentration of greenhouse gases. • Greenhouse gases cause upward pressure on global temperatures, but the actual extent is not known. • Both natural and human-caused effects on the global climate are too slow to be seen in a human lifetime.

40. Brave Political Prediction What will be done in the next 100 years to bring down the amount of CO2 released into the atmosphere in order to decrease the effects of anthropogenic global warming?

41. Brave Political Prediction What will be done in the next 100 years to bring down the amount of CO2 released into the atmosphere in order to decrease the effects of anthropogenic global warming? Nothing!

42. USA & Canada Russia & E. Europe W. Europe China India, SE Asia

44. Conclusions

45. Conclusions There is no such thing as “the environment” that can be destroyed by anthropogenic global warming.

46. Conclusions There is no such thing as “the environment” that can be destroyed by anthropogenic global warming. In the past, the Earth’s climate has been both much hotter and much colder.

47. Conclusions There is no such thing as “the environment” that can be destroyed by anthropogenic global warming. In the past, the Earth’s climate has been both much hotter and much colder. AGW might cause temperatures to increase, sea levels to rise, hurricanes to strengthen - but with imperceptible slowness.

48. Conclusions There is no such thing as “the environment” that can be destroyed by anthropogenic global warming. In the past, the Earth’s climate has been both much hotter and much colder. AGW might cause temperatures to increase, sea levels to rise, hurricanes to strengthen - but with imperceptible slowness. Even without AGW, the Earth’s climate will continue to do what it always has: fluctuate wildly - with imperceptible slowness.

49. Global Warming on Mars? 100 m

50. Human and Natural Influences on the Environment: Who’s Doing What? Rick Ulrich Dept. of Chemical Engineering Univ. of Arkansas rulrich@uark.edu Feb. 22, 2006