Thursday, November 11, 2010

Tropical Forests Thrived During Ancient Global Warming

New Scientist: Tropical Forests Thrived in Ancient Global Warming.

South America's tropical forests flourished when temperatures skyrocketed 56 million years ago. Could this mean that climate change will spare the Amazon?

Carlos Jaramillo of the Smithsonian Tropical Research Institute in Balboa, Panama, and colleagues excavated pollen and other plant remains from three sites in Colombia and Venezuela.

Their samples span the Palaeocene-Eocene Thermal Maximum (PETM), when soaring levels of greenhouse gases caused global temperatures to rise by 5 °C in about 10,000 years.

The tropical forests then faced average temperatures up to 34 °C, compared with 27 °C today, yet contrary to expectations the pollens suggest plant diversity increased.

Each sample of 150 grains of pollen from the PETM contained an average of 36 species, compared with just 24 species in samples from older, cooler times. And the rate at which new species formed was significantly higher in the PETM than before it.

The trends are puzzling because models predict that the Amazon will burn and be reduced to savannah with future climate change
Abderite LOL.

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