More Past Climate Change Reading...

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Paleoclimatology - The Study of Ancient Climates

•For much of Earth's history, the world has been ice-free (even at the poles) but these iceless periods have been interrupted by several major glaciation periods (called glacial epochs) and we are in one now. Each glacial epoch consists of multiple advances and retreats of ice fields. These ice fields tend to wax and wane in approximate 100,000, 41,000, and 21,000 year cycles. Each advance of ice is popularly known in the press as an "ice age" but it is important to note that these multiple events are just variations of the same glacial epoch. The retreat of ice during a glacial epoch is called an inter-glacial period and this is our PRESENT DAY CLIMATE system..
•The current Plio-Pleistocene Glacial Epoch had it's beginning about 3.2 million years ago and is probably linked to the tectonic construction of the Isthmus of Panama which prevented the circulation of Atlantic and Pacific waters and ultimately triggered a slow sequence of events that eventually led to cooling of the atmosphere and the formation of new ice fields by about 2.5 million years ago.
•So far we have had around 15 to 20 individual major advances and subsequent retreats of the ice field in our current glacial epoch. The last major advance of glacial ice peaked about 18,000 years ago and since that time the ice has generally been retreating (albeit with some short term interruptions).

much more... http://www.lakepowell.net/sciencecenter/paleoclimate.htm

 

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Droughts occur throughout North America, and in any given year, at least one region is experiencing drought conditions. The major drought of the 20th century, in terms of duration and spatial extent, is considered to be the 1930s Dust Bowl drought which lasted up to 7 years in some areas of the Great Plains. The 1930s Dust Bowl drought, memorialized in John Steinbeck's novel, The Grapes of Wrath, was so severe, widespread, and lengthy that it resulted in a mass migration of millions of people from the Great Plains to the western U.S. in search of jobs and better living conditions.

Just how unusual was the Dust Bowl drought?

more... http://www.ncdc.noaa.gov/paleo/drought/drght_home.html

 

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Droughts occur throughout North America, and in any given year, at least one region is experiencing drought conditions. The major drought of the 20th century, in terms of duration and spatial extent, is considered to be the 1930s Dust Bowl drought which lasted up to 7 years in some areas of the Great Plains. The 1930s Dust Bowl drought, memorialized in John Steinbeck's novel, The Grapes of Wrath, was so severe, widespread, and lengthy that it resulted in a mass migration of millions of people from the Great Plains to the western U.S. in search of jobs and better living conditions.

Just how unusual was the Dust Bowl drought?

more... http://www.ncdc.noaa.gov/paleo/drought/drght_home.html

Read on. The Dust Bowl drought was worsened by human actions.
http://www.ncdc.noaa.gov/paleo/drought/drght_history.html

In the aftermath of the Dust Bowl, it was clear that many factors contributed to the severe impact of this drought. A better understanding of the interactions between the natural elements (climate, plants, and soil) and human-related elements (agricultural practices, economics, and social conditions)of the Great Plains was needed. Lessons were learned, and because of this drought, farmers adopted new cultivation methods to help control soil erosion in dry land ecosystems. Subsequent droughts in this region have had less impact due to these cultivation practices.