Amazon Forest in Critical Danger
The vast Amazon rainforest is on the brink of being turned into desert, with catastrophic consequences for the world's climate. And the process, which would be irreversible, could begin as early as next year. The cause comes from the permanence of the El Nino climate from the Pacific that is altering the precipitation in Amazonia.
Scientists were surprised to find that the forest is rapidly approaching a "tipping point" that would lead to its total destruction. Dr Nepstead covered an area of rainforest the size of a football pitch with plastic panels to see how it would cope without rain, and expected to record only minor changes.
The trees managed the first year of drought without difficulty. In the second year, they sunk their roots deeper to find moisture, but survived. But in year three, they started dying. Beginning with the tallest the trees started to come crashing down, exposing the forest floor to the drying sun.
By the end of the third year the trees had released more than two-thirds of the carbon dioxide they had stored during the whole of their lives, accelerating climate change. This study shows that Amazonia cannot withstand more than two consecutive years of drought without breaking down.
This immense forest contains 90 billion tons of carbon, enough to increase
the rate of global warming by 50 per cent.
In 2006 the Amazon appears to be entering its second successive year of drought, raising the possibility that if the drought continues it could start dying next year. Mega-fires are expected to rapidly sweep across the drying jungle. With the trees gone, the soil will bake in the sun and the rainforest could turn into desert. This would spread drought into the northern hemisphere, including Britain, and could massively accelerate global warming with incalculable consequences. Spinning out of control this process could end in the world becoming uninhabitable – for the Amazon is the earth's largest CO2 sink.
Dr Deborah Clark from the University of Missouri, one of the world's top forest ecologists, says that "the lock has broken" on the Amazon ecosystem. She adds: the Amazon is "headed in a terrible direction".
In the current drought the Amazon rainforest has begun releasing more carbon than it is absorbing. As in Europe after the 2003 heat wave that killed 35,000 people, the woodlands are being damaged. This causes them to release more carbon dioxide than they sequester – exactly the opposite of the assumptions built into most climate computer models, which treat forests as sponges that sop up excess carbon.
After carbon emissions caused by humans, deforestation is the second principle cause of atmospheric carbon dioxide. Deforestation is responsible for 25% of all carbon emissions entering the atmosphere, by the burning and cutting of about 34 million acres of trees each year, equivalent to the area of Italy.