February 10, 2009

Amazon More Resistant To Warming Than Originally Thought

Forests in the Amazon could be less susceptible to global warming than originally thought because rainfall predictions were underestimated, a study stated.

According to Reuters, the report, released by British scientists, wants Brazil and other nations to do something to help prevent any permanent drying of the eastern Amazon, the area the vulnerable to climate change, deforestation and fires.

"The rainfall regime in eastern Amazonia is likely to shift over the 21st century in a direction that favors more seasonal forests rather than savannah," they said in this week's U.S. Proceedings of the National Academy of Sciences, released on Monday.

Seasonal forests experience both wet and dry seasons rather than the rainforest, which is eternally soaked. This change may support new kinds of trees, plants and animals.

The data contradicts past numbers that said the Amazon forest could perish and may be covered by savannah.

A 2007 statement by the U.N. Climate Panel, an overview of global warming by several experts, said: "By mid-century, increases in temperature and associated decreases in soil water are projected to lead to gradual replacement of tropical forest by savannah in eastern Amazonia."

The new study states that 19 global climate models miscalculated rainfall in the largest tropical forest when scientists contrasted the models with interpretations of climate in the 20th century.

Lowland forests have a yearly average rainfall of 94 inches. Anticipated reductions in rainfall imply that the area will still be moist enough to nourish a forest.

The experts also looked at studies of how the Amazon could respond to an overall drying out. The numbers implied that seasonal forests may stay strong against the occasional drought but overall would be exposed to fires.

"The fundamental way to minimize the risk of Amazon dieback is to control greenhouse gas emissions globally, particularly from fossil fuel combustion in the developed world and Asia," said Yadvinder Malhi, the head author from Oxford University.

However, Malhi said that Brazilian governments also had to supervise the forests more fully.

Global warming is "accompanied by an unprecedented intensity of direct pressure on the tropical forests through logging, deforestation, fragmentation, and fire use," the scientists wrote in the report.


On the Net: