Regional and Global Atmospheric Changes Chapter 21 Regional and Global Atmospheric Changes

Proof Positive!

Non-Anthropogenic Reasons Sun Spots – solar energy Changes in Earth’s orbit 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 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 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 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 : A probable temperature rise between 1.1°C and 6.4°C (2.0-11.50F) 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.

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 Thermal expansion 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 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 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. 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 Seasonal events starting earlier and ending later The top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 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 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 Pacific 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 Gulf Stream – Warm Water Intersects with Cold Water Shelf Gyre Warm-Core Eddie 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=PLBE8E58A79407AB44&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 Access to oceans for fishing and oil Increased plant production More livable climates such as twin cities