Amazon drought caused 'major' climate impact

2011-02-04 13:17

kalahari.com

  • Climate Change
    Read more about the environmental changes and challenges the world faces. Now R261.00
    buy now

Rio de Janeiro - A widespread drought in the Amazon rain forest last year was worse than the "once-in-a-century" dry spell in 2005 and may have a bigger impact on global warming than the US does in a year, British and Brazilian scientists said on Thursday.

More frequent severe droughts like those in 2005 and 2010 risk turning the world's largest rain forest from a sponge that absorbs carbon emissions into a source of the gases, accelerating global warming, the report found.

Trees and other vegetation in the world's forests soak up heat-trapping carbon dioxide as they grow, helping cool the planet, but release it when they die and rot.

"If events like this happen more often, the Amazon rain forest would reach a point where it shifts from being a valuable carbon sink slowing climate change to a major source of greenhouse gases that could speed it up," said lead author Simon Lewis, an ecologist at the University of Leeds.

The study, published in the journal Science, found that last year's drought caused rainfall shortages over a three million square kilometre expanse of the forest, compared with 1.9 million square kilometres in the 2005 drought.

Emissions

It was also more intense, causing higher tree mortality and having three major epicentres, whereas the 2005 drought was mainly focused in the south-western Amazon.

As a result, the study predicted the Amazon forest would not absorb its usual 1.5 billion tonnes of carbon dioxide from the atmosphere in both 2010 and 2011. In addition, the dead and dying trees would release five billion tonnes of the gas in the coming years, making a total impact of about eight billion tonnes, according to the study.

In comparison, the US emitted 5.4 billion tonnes of carbon dioxide from fossil fuel use in 2009.

The combined emissions caused by the two droughts were probably enough to have cancelled out the carbon absorbed by the forest over the past 10 years, the study found.

The widespread drought last year dried up major rivers in the Amazon and isolated thousands of people who depend on boat transportation, shocking climate scientists who had billed the 2005 drought as a once-in-a-century event.

The two intense dry spells fit predictions by some climate models that the forest will face greater weather extremes this century, with more intense droughts making it more vulnerable to fires, which in turn could damage its ability to recover.

Under the more extreme scenarios, large parts of the forest could turn into a savannah-like ecosystem by the middle of the century with much lower levels of animal and plant biodiversity. Although human-caused deforestation in Brazil has fallen sharply in recent years, scientists say the forest is still vulnerable.

Vicious cycle

A crucial question is whether the droughts are being driven by higher levels of greenhouse gases or are an anomaly, Lewis said. If they are driven by global warming, a vicious cycle of warmer temperatures and droughts could conceivably lead to a large-scale transformation of the forest over a period of decades.

"You could quite rapidly move to a much drier Amazon with less forest there," Lewis said.

The research was a collaboration among scientists at the University of Leeds and the University of Sheffield in Britain and Brazil's Amazon Environmental Research Institute.

Read more on:    climate change
NEXT ON NEWS24X

Read News24’s Comments Policy

24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
4 comments
Add your comment
Comment 0 characters remaining
 

Inside News24

 
 
Traffic
Lottery
 
  • Wednesday Epping - 15:22 PM
    Road name: N7
    TRAFFIC LIGHTS not working at Bofus Circle
  • Wednesday Wellington - 14:45 PM
    Road name: R44 Northbound
    ACCIDENT between Wellington and Hermon
 
More traffic reports...
 

Jobs in Cape Town [change area]

Property [change area]

Travel - Look, Book, Go!

Escape winter, head to Mauritius

Escape winter by spending 7 nights in Mauritius' tropical bliss from R13 215 per person sharing. Includes return flights, airport transfers and accommodation. Book now!

Kalahari.com - shop online today

Get many eggs in one basket!

Gaming bundles: 2 Super Hits games for R99, 3 Disney games for R99 and more + exclusive accessory bundles only available on kalahari.com. While stocks last. Shop now!

25% off bestselling books!

The Real Meal Revolution by Tim Noakes, Jeffrey Archer’s Be Careful What You Wish for, Man’s Search for Meaning by Victor E. Frank and many more titles. Shop now!

Up to 25% off electronics

Buy top electronics and save up to 25%. Such as kalahari.com’s 1# selling product the gobii eReader, Patriot X Porter flash drive, Asus Nexus 7” 3G tablet, Samsung Galaxy SIII, Lenovo G580 Notebook and many more. Shop now!

DStv HD PVR Decoder now R949

The DStv HD PVR Decoder has further revolutionised the television experience with lifelike viewing, sharper images, more vibrant colours and precision picture quality. Now R949, save R550. Offer valid while stocks last. Shop now!

Up to 30% off appliances & homeware

Save up to 30% on appliances and homeware this Easter! Offer valid while stocks last. Shop now.

OLX Free Classifieds [change area]

Samsung Galaxy s4

Mobile, Cell Phones in South Africa, Western Cape, Cape Town. Date October 24

Best bargain in big bay

Real Estate, Houses - Apartments for Sale in South Africa, Western Cape, Cape Town. Date October 25

VW Golf 6, 1.6 Trendline (Excellent condition)

Vehicles, Cars in South Africa, Western Cape, Cape Town. Date October 25

BlackBerry Bold 9780

BlackBerry 6 Engage your world with BlackBerry 6 OS on the...

From R3049.00

I'm shopping for:

Horoscopes
Aquarius
Aquarius

You may find yourself fascinated by something which could draw you in to obsessively exploring this subject in depth....read more

There are new stories on the homepage. Click here to see them.
 
English
Afrikaans
isiZulu

Hello 

Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.


Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Settings

Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.








Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.