1. Regional and Global Atmospheric Changes
Chapter 21
Regional and Global Atmospheric Changes

2. Proof Positive!

3. Non-Anthropogenic Reasons
Sun Spots – solar energy
Changes in Earth’s orbit
Changes in axis tilt and wobble

4. Is Global Warming Anthropogenic?
Svante Arrhenius
A Swedish scientist first to claim in 1896 that fossil fuel combustion may eventually result in enhanced global warming.
Charles Keeling
Produce concentration curves for atmospheric CO2 starting in 1958
280ppm = preindustrial levels
392ppm levels in 2011 add 2ppm yearly
350ppm considered safe for life as we know it
450ppm or 20C change = serious weather change

5. Keeling Curve Winter High & Summer Low
Scientists are pushing for CO2 caps that will stabilized us at 450 ppm in the next few decades. Many believe this goal isn't politically feasible, and prefer 550 ppm
Winter High & Summer Low

6. Temperature and Carbon Dioxide
In the 1980's the global annual mean temperature curve started to rise

8. Greenhouse Gasses
Water Vapor - absorbs and releases energy

9. Greenhouse Gases
Water Vapor - absorbs and releases energy

10. Intergovernmental Panel on Climate Change http://www.ipcc.ch/

11. IPCC 4th report 2007
The IPCC predicts that by the end of the 21st century climate change will result in :
A probable temperature rise between 1.1°C and 6.4°C ( F) by 2100.
A sea level rise most likely to be 28-43cm (11-17inches)
Arctic summer sea ice disappearing in second half of century
An increase in heat waves very likely
A likely increase in tropical storm intensity.

12. Effects of Temperature Changes
Change wind and weather patterns Redistribute global moisture Shift Agricultural Areas Alter World’s Biomes Alter Some Ocean Currents Increase Sea Levels Flood Coastal Wetlands and Cities Increase Waterborne and Insect-transmitted diseases

13. Why Ocean’s Rise
Thermal expansion
Additions of water from melting ice

14. Antarctica

15. Major Ice Caps - Anarctica
1. Antarctica
90% of world’s ice, ocean’s rise 200Ft
Landmass based
Larsen B Ice Shelf, 650 feet thick about the size of Rhode Island
The Ross Ice Shelf is roughly as big as Texas – attached to the ice sheets that cover almost 98% of the Antarctic continent.

16. Greenland Ice Cap

17. Major Ice Caps - Greenland
Sea levels rise 23 feet if the entire ice sheet melted
Landmass Based
Florida and Sea Level Changes 550ppm ice free poles = meters of sea rise

18. Glacial Moulins

19. Major Ice Caps - The Arctic
Temperature rise of 4-7C by 2100
All Ice Shelves

20. Arctic Ice Cap

21. Melting Glaciers

22. Albedo
The fraction of radiation striking a surface that is reflected by that surface High Albedo - reflecting most of the energy Low Albedo - absorbing most of the energy

23. Proof of Global Warming
1. Global sea level rose about 17 centimeters (6.7 inches) in the last century. The rate in the last decade, however, is nearly double that of the last century.
2. Average Arctic temperatures increased at almost twice the global average rate in the past 100 years. Shrinking glaciers and ice caps.
Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years. Despite an unusually deep solar minimum in
Seasonal events starting earlier and ending later
The top 700 meters (about 2,300 feet) of ocean showing warming of degrees Fahrenheit since 1969
The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since The U.S. has also witnessed increasing numbers of intense rainfall events.

24. Warmer Temperatures; Different Organisms
Changes Occur In
Distributions
Population Sizes
Population Density
Wildlife Behavior

25. Periods of Climate Change
Glacial (100,000 year average) Interglacial (12,000 year average)

26. Florida’s Glacial Shoreline

27. Extent of Last Glacial Period
Little Ice Age

28. Analyzing atmospheric History
1. Air Bubbles in Ice Cores 2. Analyze sediments in lakes, ponds and swamps for pollen & fossils

29. Ice Core Sample

30. 6 Geostrophic Gyres North Atlantic Gyre South Pacific Gyre
South Atlantic Gyre
North Pacific Gyre
South Pacific Gyre
The Indian Ocean Gyre
Antarctic Circumpolar Current

31. Satellite Image of Ocean Gyres Based on Thermal Differences

32. Satellite Image of Gulf Stream and Major Eddies
Gulf Stream – Warm Water
Intersects with Cold Water Shelf Gyre
Warm-Core Eddie
Cold-Core Eddie

33. North Atlantic Current
Cooling increases salinity and density

34. Where are we?

35. Positive Feedback - Clathrates
Methane Clathrates
In Siberian permafrost & ocean floor sediments are vast deposits of gas-filled ice (methane) called clathrates.
Tundra - permafrost

36. Positive Feedback
CO2 emissions, copious as they are, may just wind up pulling the trigger on the clathrate gun.

37. You Tubes

38. Cow Gas

39. Methane Emissions
Landfills (35%) Domesticated Livestock (26%) Natural Gas and Oil Systems (20%) Coal Mining (10%) Rice Paddies

40. Resisting Change Other Pollutants Cool the Atmosphere
known as the “aerosol” effect
Sulfur emissions
Volcanic Eruptions
Jet Contrails
Increased cloud cover from evaporation
Increased absorption of CO2 in ocean’s

41. Mitigation Mitigation of Global Climate Change
Alternatives to fossil fuels
Sequestering Carbon in Trees
Sequestering Carbon (technology)
Fertilizing the Ocean with Iron
Fertilizing the stratosphere with sulfur

42. Solutions?
Iron in the oceans increases phytoplankton production - could seed the oceans?

43. Benefits of Global Warming
Access to oceans for fishing and oil
Increased plant production
More livable climates such as twin cities