Amazon 'desert' report under fire

Posted: 19 September 2006

The Amazon rainforest is at risk of turning into desert in the near future, with catastrophic consequences for the world's climate, according to research reported in The Independent newspaper in July, and reproduced in this website. However aspects of the report have been criticised by one of the scientists involved.

Aerial view of the Amazon forest. © Greenpeace / Beltra, Daniel
Aerial view of the Amazon forest. © Greenpeace / Beltra, Daniel
Aerial view of the Amazon forest.© Greenpeace / Daniel Beltra
The award winning author and environmental journalist Geoffrey Lean in Manaus and leading science writer Fred Pearce were reporting on studies in Amazonia carried out by the Woods Hole Research Center.

According to the newspaper these studies concluded that the forest cannot withstand more than two consecutive years of drought without breaking down. This in turn, scientists said, would spread drought into the northern hemisphere and could massively accelerate global warming - a process that might end in the world becoming uninhabitable.

The research - carried out by the Massachusetts-based Woods Hole centre in Santarem on the Amazon river - involved covering a patch of rainforest the size of a football pitch with plastic panels to see how the trees cope without rainfall.

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 treesstarted 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.

The two journalists said the Amazon now appears to be entering its second successive year of drought, raising the possibility that it could start dying next year. If this happens the forest could release 90 billion tons of carbon, 'enough in itself to increase the rate of global warming by 50 per cent'.

They said that Dr Dan Nepstead, who started the experiment in 2002, expects "mega-fires" 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, said the research shows that "the lock has broken" on the Amazon ecosystem. The Amazon, she said, is "headed in a terribledirection".

We now learn that The Independent report later came under fire from Dr Nepstead. Writing in the Woods Hole website on August 8, Dr Nepstead, said the article contained 'many statements that I do not support'.

"To clarify, our results do not show that the rainforest 'could become a desert'. In the third paragraph, the piece implies that I support the position that drought in the Amazon will lead to drought that would spread to Britain, with the world spinning out of control, becoming uninhabitable. That is simply not true.

"What our work does show is that the drought we imposed caused big trees to die more than small trees, which was a surprise. We also know that the amounts of carbon that may be going to the atmosphere following Amazon droughts are probably big enough to accelerate global warming. Currently trends suggest that a big chunk of the Amazon forest will probably be displaced by fire-prone scrub vegetation; global warming will probably exacerbate this trend.

"The challenges we are confronting and those that we will be faced with in the future are significant. The world's tropical rainforests will be changed in important ways by global warming. But public understanding of these processes is not served by evoking apocalyptic images..."

The full text of The Independent report can be found at http://news.independent.co.uk/environment/article1191932

A second fuller report on drought and destruction in the Amazon was also carried by The Independent on the same day (July 23, 2006). It can be accessed by clicking on http://news.independent.co.uk/environment/article1191880.ece

Fred Pearce is the author of 'The Last Generation' (Eden Project Books),published earlier this year.