Regional and Global Atmospheric Changes Chapter 20

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 CO 2 starting in ppm = preindustrial levels 2.350ppm considered safe for life as we know it 3.Passed 400ppm in 2013 / add 2ppm yearly & increasing 4.450ppm or 2 0 C change = serious climate 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

In the 1980's the global annual mean temperature curve started to rise

Greenhouse Gasses Water Vapor - absorbs and releases energy / 1X / 20X / 300X

Intergovernmental Panel on Climate Change

Effects of Temperature Changes 1.Change wind and weather patterns 2.Redistribute global moisture 3.Shift Agricultural Areas 4.Alter World’s Biomes 5.Alter Some Ocean Currents 6.Increase Sea Levels 7.Flood Coastal Wetlands and Cities 8.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  rise/florida.shtml rise/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 Seasonal events starting earlier and ending later 3.The top 700 meters (about 2,300 feet) of ocean showing warming of degrees Fahrenheit since 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.

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. A79407AB44&index=20http:// A79407AB44&index=20 1.

Methane Sources 1.Landfills 2.Domesticated Livestock 3.Natural Gas and Oil Systems 4.Coal Mining 5.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 CO 2 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