Amazon drought suggests ‘grim future’ for region
A severe drought across the Amazon rainforest in 2010 has
devastated swathes of the two million square mile region.
New research published in Science reports on dry riverbeds,
millions of dead trees and an increased number of wildfires. The
sum-total of these environmental changes meant that instead of
absorbing carbon, as the 'lungs of the Earth' usually does, the
Amazon will emit over 8 billion tonnes of CO2 as a result of the
drought, more than China emitted in 2009.
The Daily Mail states, "Around 60,000 people went hungry as
water became contaminated and millions of fish died," while, "The
dry spell was also disastrous for trees, amphibians and other
wildlife." River levels were so low it caused more than 20
municipalities to declare a state
of emergency. In 2005, the Amazon suffered what was described
as a
'once in a century' drought, however, the dry period in 2010
appears to have been more damaging. Although the research is still
at an initial stage, satellite
images here indicate the afflicted areas of the forest are
considerably larger.
The Rio Negro river in 2010 (above), and 2008 (below). The
river reached a record low this year. via NASA
Earth Observatory.
The Guardian reports, "the vast forest is on the verge of a
tipping point, where it will stop absorbing greenhouse gas
emissions and instead increase them." When alive, trees are able to
store CO2 and normally the Amazon would be expected to absorb
approximately 1.5 billion tonnes a year. But when trees die CO2 is
released back into the atmosphere. In cases of extreme drought such
as this one, millions of trees were killed and consequently around
8 billion tonnes of CO2 were emitted.
Researchers fear that if droughts like this continue to happen
in the future the Amazon will cease to be a valuable "carbon sink"
and instead become a formidable emitter of CO2. Such a change would
make it significantly harder for the world to reduce emissions and
mitigate climate change. But a definitive link between the two
recent droughts and long-term climate change has not been
established. Dr
Simon Lewis, the project's lead researcher, commented:
"One possibility is that this is just a
natural climatic variation and in the future we might not see any
more of these type of droughts. The alternative is it's associated
with high greenhouse gas concentrations in the atmosphere, it's
related to climate change and if that's the case then we will see
these droughts increasing in intensity and frequency into the
future."
Lewis also remarks,
"Having two events of this magnitude in
such close succession is extremely unusual, but is unfortunately
consistent with those climate models that project a grim future for
Amazonia."
Lewis and co-author Dan Nepstad previously intervened over a
Sunday Times story claiming the IPCC was making bogus claims about
the Amazon being sensitive to changes in rainfall - an incident
described by sceptic lobbyists and commentators as 'Amazongate'.
At the time Lewis stated that "the IPCC statement itself is poorly written,
and bizarrely referenced, but basically correct ... Indeed, some
leading models of future climate change impacts show a die-off of
more than 40% Amazon forests..."
Lewis complained to the Press Complaints Commission about the
article, which was subsequently retracted by the Sunday Times which
also published an apology.
Substantial changes to the Amazon caused by drought are
potentially irreversible and would have serious consequences for
the world's effort to reduce anthropogenic global warming. Further
research into the full effects of the 2010 drought is on going with
more results expected later this year.