Global warming 60m years ago improved Tropical forest diversity

Friday, November 12, 2010

WASHINGTON - Global warming may not have any adverse effect on the Tropical forests, as scientists have suggested that nearly 60 million years ago rainforests prospered at temperatures that were 3-5 degrees higher and at atmospheric carbon dioxide levels 2.5 times today’s levels.

“We’re going to have a novel climate scenario,” said Joe Wright, of the Smithsonian Tropical Research Institute, in a 2009 Smithsonian symposium on Threats to Tropical Forests.

Carlos Jaramillo, staff scientist at the Smithsonian Tropical Research Institute, and colleagues examined pollen trapped in rock cores and outcrops-from Colombia and Venezuela-formed before, during and after an abrupt global warming event called the Paleocene-Eocene Thermal Maximum that occurred 56.3 million years ago.

The world warmed by 3-5 degrees C. Carbon dioxide levels doubled in only 10,000 years. Warm conditions lasted for the next 200,000 years.

Contrary to speculation that tropical forests could be devastated under these conditions, forest diversity increased rapidly during this warming event.

New plant species evolved much faster than old species became extinct. Pollen from the passionflower plant family and the chocolate family, among others, were found for the first time.

“It is remarkable that there is so much concern about the effects of greenhouse conditions on tropical forests,” said Klaus Winter, of the STRI.

“However, these horror scenarios probably have some validity if increased temperatures lead to more frequent or more severe drought as some of the current predictions for similar scenarios suggest,” added Winter.

Evidence from this study has indicated that moisture levels did not decrease significantly during the warming event. Overall results indicate that tropical forests fared very well during this short and intense warming period.

The study has been reported in the journal Science. (ANI)

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