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Climate Record Suggesting Severe Tropical Droughts as Northern Temperatures Rise

May 13, 2011 Comments off

terradaily


Laguna Pumacocha in the Peruvian Andes.

A 2,300-year climate record Universityof Pittsburgh researchers recovered from an Andes Mountains lake reveals that as temperatures in the Northern Hemisphere rise, the planet’s densely populated tropical regions will most likely experience severe water shortages as the crucial summer monsoons become drier. The Pitt team found that equatorial regions of South America already are receiving less rainfall than at any point in the past millennium.

The researchers report in the Proceedings of the National Academy of Sciences (PNAS) that a nearly 6-foot-long sediment core from Laguna Pumacocha in Peru contains the most detailed geochemical record of tropical climate fluctuations yet uncovered. The core shows pronounced dry and wet phases of the South American summer monsoons and corresponds with existing geological data of precipitation changes in the surrounding regions.

Paired with these sources, the sediment record illustrated that rainfall during the South American summer monsoon has dropped sharply since 1900-exhibiting the greatest shift in precipitation since around Read more…