Alarming drought in the Amazon could have global consequences

Some of the most severe droughts in 2005 and 2010 reduced the ability of Amazon to absorb carbon dioxide from the atmosphere. Drought hinders the growth of plants, absorb carbon, and increases the number of forest fires, resulting in the release of carbon into the atmosphere.

February 4, 2011. The largest tropical forest in the world — the Amazon (Other name: the Amazonian lowlands)
— Last year experienced something exceptional — a drought. This is certainly not a drought that caused the earth to crack the American Southwest, or as in the north-west, the center of Australia, but the drought has slowed the growth of trees or completely destroy them.

Over the past 5 years, this was the second such drought, and scientists studying the forest, trying to understand why there was such a drought, and what are the consequences for the planet.

The drought in 2005 was so unusual that scientists called it — "the event once in 100 years" — something expected, which happens only once every 100 years.

"Those two rare cases that we've seen alarming" — says Simon Lewis, a forest ecologist at the University of Leeds in the UK, two more drought in the Amazon. Lewis noted that a number of computer models that calculate the effects of climate change, did predict that some areas of our planet will soon become drier.

"And those two rare events coincide with the forecast that in the coming decades Amozoniya may suffer from severe drought," — he said.

The impact of drought on forests

When writing in the journal "Science", Lewis and his team of scientists say they may have a drought caused by the movement of water to the North Atlantic Ocean, especially its warm waters. These changes in the movement of moisture transfer to the north, leaving the Amazon rain it normally does.

Drought can create heterogeneous forest — a thin, small and different in their species composition of trees. This, in turn, could affect the Earth's climate. As trees grow, they absorb carbon dioxide from the atmosphere and accumulate it, so a big forest (as in Amazon) plays the role of a sort of "shell", which "merges" the carbon dioxide.

But drought slows down the movement of carbon, thus, more carbon remains in the atmosphere, and this could lead to a "heat" of the planet.

If the wood is too dry, the air can get into the capillaries that carry water through the whole tree — a phenomenon similar to the presence of air in the fuel system of the engine — and the tree dies. If you die a lot of trees, it can affect the atmosphere.

"As the dead trees rot and get rid of carbon from their trunks and roots to the atmosphere as carbon dioxide, we can see that it becomes a source of carbon emissions," — says Lewis.

Fire and agriculture

Drought is very broad and covers an area the size of Argentina. It affects the parts of the Amazon, who are particularly vulnerable — its southern border.

Michael Jenkins, director of a research organization called the «Forest Trends» says "it looks like a map of the epicenters of drought with a well-defined boundary of the forest and this is an area where there is agriculture, increasingly expanding deep into the Amazon."

Where agriculture, there is a fire, as a means of cleansing the land under plantations or cattle grazing. And fire exacerbates drought.

"You embed the fire" — Jenkins says — "you are changing a lot of forests, you them Sears. When the drought is, the wood is not in the same condition as before the drought. "

Last year, during the dry season, smoke from fires broke flights and led to the closure of airports in Bolivia, and the country declared a state of emergency on its own territory in the Amazon.

Translation: Anna Krasnov
Source: NPR

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