Studying prehistoric climate can help forecast future changes

November 25th, 2008 - 4:46 pm ICT by ANI  

Washington, Nov 25 (ANI): A new research has indicated that studying prehistoric warm periods can help in forecasting future changes in climate.

The research was conducted by the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) group, led by the U.S. Geological Survey (USGS).

For the research, scientists examined fossils from 3.3 to 3.0 million years ago, known as the mid-Pliocene warm period.

The mid-Pliocene experienced the most extreme warming over the past 3.3 million years.

Global average temperatures were 2.5 degree Celsius greater than today and within the range projected for the 21st century by the Intergovernmental Panel on Climate Change.

Exploring the mid-Pliocene will further understanding on the role of ocean circulation in a warming world, the impacts of altered storm tracks, polar versus tropical sensitivity, and the impacts of altered atmospheric CO2 and oceanic energy transport systems, said USGS scientist Harry Dowsett, also lead scientist for PRISM.

We used fossils dated to the mid-Pliocene to reconstruct sea surface and deepwater ocean temperatures, and will continue research by studying specific geographic areas, vegetation, sea ice extent and other environmental characteristics during the Pliocene, he added.

Since CO2 levels during the mid-Pliocene were only slightly higher than todays levels, PRISM research suggests that a slight increase in our current CO2 level could have a large impact on temperature change.

Research also shows warming of as much as 18 degree C, bringing temperatures from 2 degree C to 16 degree C, in the high latitudes of the North Atlantic and Arctic Oceans during the mid-Pliocene.

Warming in the Pacific, similar to a present day El Nino, was a characteristic of the mid-Pliocene.

Global sea surface and deep water temperatures were found to be warmer than those of today, impacting the oceans circulation system and climate.

Data suggest the likely cause of mid-Pliocene warmth was a combination of several factors, including increased heat transport from equatorial regions to the poles and increased greenhouse gases.

According to Thomas Armstrong, Senior Advisor to USGS Global Change Programs, This is the most comprehensive global reconstruction for any warm period and emphasizes the importance of examining the past state of Earths climate system to understand the future. (ANI)

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