Download PP3(Ch20-28)Climate Change

Chapter 20
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
Swedish scientist states 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
350ppm considered safe for life as we know it
Passed 400ppm in 2013 / add 2ppm yearly & increasing
450ppm or 20C change = serious climate 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
In the 1980's the global
annual mean
temperature curve
started to rise
Greenhouse Gasses
100-120 / 1X
10-20 / 20X
100-120 / 300X
Water Vapor - absorbs and releases energy
Intergovernmental Panel on
Climate Change
http://www.ipcc.ch/
Effects of Temperature Changes
1.
2.
3.
4.
5.
6.
7.
8.
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
1. Additions of water from melting ice
Antarctica
 90% of world’s ice, ocean’s rise 200Ft
 Landmass based
Larsen B Ice Shelf, 650 feet
thick size of Rhode Island
Ross Ice Shelf size of
Texas
Greenland
Ice Cap
Sea levels rise 23’ if ice melted
Landmass Based
http://geology.com/sea-levelrise/florida.shtml
Glacial Moulin's
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
The Arctic
Melting Glaciers
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.
Extent of
Last Glacial
Period
Analyzing atmospheric History
1. Air Bubbles in Ice Cores
2. Analyze sediments in lakes, ponds and swamps for pollen
& micro-fossils
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
North Atlantic Current
Positive Feedback - Clathrates
Methane Clathrates
In Siberian permafrost & ocean floor sediments are vast
deposits of gas-filled ice (methane) called clathrates.
Positive Feedback
CO2 emissions, copious as they are, may just wind up pulling the trigger on
the clathrate gun.
1. http://www.youtube.com/watch?v=oa3M4ou3kvw&playnext=1&list=PLBE8E58
A79407AB44&index=20
1. http://www.youtube.com/watch?v=YegdEOSQotE&feature=related
Methane Sources
1.
2.
3.
4.
5.
Landfills
Domesticated Livestock
Natural Gas and Oil Systems
Coal Mining
Rice Paddies
Aerosol Effect
Other Pollutants Cool the Atmosphere
1. Sulfur emissions
2. Volcanic Eruptions
3. Jet Contrails
4. Increased cloud cover from evaporation
5. Increased absorption of CO2 in ocean’s
Mitigation
1. Alternatives to fossil fuels
2. Sequestering Carbon in Trees
3. Sequestering Carbon
4. Fertilizing the Ocean with Iron
5. Fertilizing the stratosphere with sulfur
Benefits of Global Warming
1. Access to oceans for fishing and oil
2. Increased plant production
1. More livable climates such as twin cities