A study by the Woods Hole Research Centre concluded that the Amazon forest is at imminent risk of turning into desert, with disastrous consequences for the world’s climate. The research, which concluded that the forest cannot withstand more than two consecutive years of drought without breaking down, has taken even the scientists conducting it by surprise.
When Dr Dan Nepstead started the experiment in 2002 by covering a chunk of rainforest the size of a football pitch with plastic panels to see how it would cope without rain he surrounded it with sophisticated sensors, expecting 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 year the trees had released more than two-thirds of the carbon dioxide they have stored during their lives, helping to act as a break on global warming. Instead they began accelerating the climate change.
Scientists say that the effects of the forest breakdown would spread drought into the northern hemisphere and could massively accelerate global warming with incalculable consequences, spinning out of control, a process that might end in the world becoming uninhabitable.
Dr Nepstead expects “mega-fires” rapidly to sweep across the drying jungle. With the trees gone, the soil will bake in the sun and the rainforest could become desert.
Dr Deborah Clark from the University of Missouri, one of the world’s top forest ecologists, says the research shows that “the lock has broken” on the Amazon ecosystem. She adds: the Amazon is “headed in a terrible direction”.
The forest contains 90 billion tons of carbon; if it starts dying it could release vast quantities of carbon, increasing the rate of global warming by 50%.
Date: 23 July 2006