Chapter 21
Regional and
Global
Atmospheric
Changes
Proof Positive!
Non-Anthropogenic Reasons
1. Sun Spots – solar energy
2. Changes in Earth’s orbit
3. Changes in axis tilt and wobble
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
1.
2.
3.
4.
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
Keeling Curve
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
http://co2now.org/Current-CO2/CO2-Now/annual-co2.html
Winter
High &
Summer
Low
Temperature and Carbon Dioxide
In the 1980's the
global annual mean
temperature curve
started to rise
Greenhouse Gasses
Water Vapor - absorbs and releases energy
Greenhouse Gases
Water Vapor - absorbs and releases energy
Intergovernmental Panel on
Climate Change
http://www.ipcc.ch/
IPCC 4th report 2007
The IPCC predicts that by the end of the 21st
century climate change will result in :
1. A probable temperature rise between 1.1°C and 6.4°C (2.011.50F) by 2100.
2. A sea level rise most likely to be 28-43cm (11-17inches)
3. Arctic summer sea ice disappearing in second half of century
4. An increase in heat waves very likely
5. A likely increase in tropical storm intensity.
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
Why Ocean’s Rise
1. Thermal expansion
2. Additions of water from melting ice
Antarctica
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.
Greenland Ice Cap
Major Ice Caps - Greenland
2. Greenland
• Sea levels rise 23 feet if the entire ice sheet melted
• Landmass Based
• Florida and Sea Level Changes 550ppm ice free
poles = 60-70 meters of sea rise
• http://geology.com/sea-level-rise/florida.shtml
Glacial Moulins
Major Ice Caps - The Arctic
3. The Arctic
• Temperature rise of 4-7C
by 2100
• All Ice Shelves
Arctic Ice Cap
Melting Glaciers
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
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.
3. 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 2007-2009
3. Seasonal events starting earlier and ending later
3. The top 700 meters (about 2,300 feet) of ocean showing warming of 0.302
degrees Fahrenheit since 1969
3. 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 1950. The U.S. has also witnessed increasing
numbers of intense rainfall events.
Warmer Temperatures; Different
Organisms
Changes Occur In
Distributions
Population Sizes
Population Density
Wildlife Behavior
Periods of Climate Change
Glacial (100,000 year average)
Interglacial (12,000 year average)
Florida’s Glacial Shoreline
Extent of
Last Glacial
Period
Little Ice Age
1550-1850
Analyzing atmospheric History
1. Air Bubbles in Ice Cores
2. Analyze sediments in lakes, ponds and
swamps for pollen & fossils
Ice Core Sample
6 Geostrophic Gyres
North Atlantic Gyre
South Atlantic Gyre
North Pacific Gyre
South Pacific Gyre
The Indian Ocean Gyre
Antarctic Circumpolar Current
Satellite Image of Ocean Gyres
Based on Thermal Differences
Satellite Image of Gulf
Stream and Major
Eddies
1. Gulf Stream – Warm
Water
2. Intersects with Cold
Water Shelf Gyre
3. Warm-Core Eddie
4. Cold-Core Eddie
North Atlantic Current
Cooling increases salinity and density
Where are we?
Positive Feedback - Clathrates
Methane Clathrates
In Siberian permafrost & ocean floor sediments are vast
deposits of gas-filled ice (methane) called clathrates.
Tundra - permafrost
Positive Feedback
CO2 emissions, copious as they are, may just wind up pulling the trigger on
the clathrate gun.
You Tubes
http://www.youtube.com/watch?v=oa3M4ou3kvw&playnext=1&list=PL
BE8E58A79407AB44&index=20
http://www.youtube.com/watch?v=YegdEOSQotE&feature=related
Cow Gas
Methane Emissions
Landfills (35%)
Domesticated Livestock (26%)
Natural Gas and Oil Systems (20%)
Coal Mining (10%)
Rice Paddies
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
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
Solutions
?
Iron in the oceans
increases phytoplankton
production - could seed
the oceans?
Benefits of Global Warming
1. Access to oceans for fishing and oil
2. Increased plant production
3. More livable climates such as twin cities