Positive reaction to drought
Latest study by researchers at the University of Arizona shows that Amazon forest has developed very well following the drought. Previous forecasts suggested that because of lack of rain, forests located along the Amazon will begin to dry after only a month.
"Despite fears that trees will be on the ground, forests have responded positively to droughts, at least in the short term," said Scott R. Saleska, author of the study. He added that development of forests is a very interesting and surprising response to supplement heat.
For instance, in 2005, when drought has reached the maximum at the beginning of the dry season from July to September, the trees have become significantly more green, indicating increased photosynthetic activity.
"We've looked at pictures of the mattress, but we used only data from the ground, even during 2005," said Saleska Professor, Department of Ecology and biology of the American University of Sao Paulo.
American and Brazilian researchers say that Amazon jungle had even some advantages from the dry season, because some species have developed better than usual. Research scientists have not examined so far how virgin forest reacts to drought. Previous climate models showed that, in contrast, photosynthesis in the Amazon will cease immediately after the drought. Theoretically, the trees would have absorbed increasingly less carbon dioxide, which would have led to increased global warming.
But forest reaction was fortunately good for us and for the planet.
Amazon jungle is "dried", but will survive global warming
Recent studies have shown that the Amazon is less vulnerable to global warming than was thought until now, because the models used in the simulations did not estimated well the volume of rainfalls. British authors of the studies showed that Brazil was forced to seek help in stopping the phenomenon of drying the eastern area of the Amazon jungle, considered irreversible process caused by global warming, deforestation and forest fires.
In the bulletin of the US National Academy of Sciences, British researchers noted that "the regime of precipitation in eastern Amazonia will help in this century seasonal vegetation development rather than the specific savannahs. Seasonal vegetation component of Amazonian forests enjoys warm and wet seasons. The climate favours the development of new species of trees, plants and fauna. And these findings are in contrast with previous projections, according to which the forest this area would turn into savannah.
A 2007 report by the UN Climate Agency, the base considered by experts in global warming, noted that "in the middle of this century, the phenomenon of rising average temperatures, accompanied by the evaporation of soil water will cause gradual replacement of tropical forest by savannah specific vegetation. Yet the latter study revealed that all 19 previous projections on climate change underestimated the amount of rainfall in the region, the statement based on measurements made during the last century. The annual volume of rainfall in the Amazon is about 2400 mm, and global warming cannot reduce this level under the minimum amount needed by the forest to exist.
Experts have examined also how Amazon forest will act on global warming: there will be flexibility during periods of drought, but will become more vulnerable to fire. The researchers stressed that fundamental method by which to protect the Amazon against global warming is to reduce global emissions of greenhouse gases.