The vast Amazon rainforest
is on the brink of being turned into desert, with catastrophic consequences for
the world's climate, alarming research suggests. And the process, which would
be irreversible, could begin as early as next year.
Studies by the blue-chip
Woods Hole Research Centre, carried out in Amazonia, have concluded that the forest
cannot withstand more than two consecutive years of drought without breaking down.
Scientists
say that this would spread drought into the northern hemisphere, including Britain,
and could massively accelerate global warming with incalculable consequences,
spinning out of control, a process that might end in the world becoming uninhabitable.
The
alarming news comes in the midst of a heatwave gripping Britain and much of Europe
and the United States. Temperatures in the south of England reached a July record
of 36.3C on Tuesday. And it comes hard on the heels of a warning by an international
group of experts, led by the Eastern Orthodox "pope" Bartholomew, last
week that the forest is rapidly approaching a "tipping point" that would
lead to its total destruction.
The research carried out by the Massachusetts-based
Woods Hole centre in Santarem on the Amazon river 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.
As we report today on pages 28 and 29, the Amazon now appears to be
entering its second successive year of drought, raising the possibility that it
could start dying next year. The immense forest contains 90 billion tons of carbon,
enough in itself to increase the rate of global warming by 50 per cent.
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".
Fred
Pearce is the author of 'The Last Generation' (Eden Project Books), published
earlier this year