Amazon basin becoming carbon emitter

2012-01-18 23:17

Paris - The Amazon Basin, traditionally considered a bulwark against global warming, may be becoming a net contributor of carbon dioxide (CO2) as a result of deforestation, researchers said on Wednesday.

In an overview published in the journal Nature, scientists led by Eric Davidson of the Woods Hole Research Centre in Massachusetts say the Amazon is "in transition" as a result of human activity.

Over 50 years, the population has risen from six million to 25 million, triggering massive land clearance for logging and agriculture, they said.

The Amazon's carbon budget - the amount of CO2 that it releases into the atmosphere or takes from it - is changing although it is hard to estimate accurately, they said.

"Deforestation has moved the net basin-wide budget away from a possible late 20th-century net carbon sink and towards a net source," according to their paper.

Mature forests such as the Amazon are big factors in the global-warming equation.

Their trees suck up CO2 from the atmosphere through the natural process of photosynthesis.


But when they rot or are burned, or the forest land is ploughed up, the carbon is returned to the air, adding to the greenhouse effect.

The paper estimates that the biomass of the Amazon contains a whopping 100bn tons of carbon - the equivalent of more than 10 years of global fossil-fuel emissions.

Global warming, unleashing weather shifts, could release some of this store, it warned.

"Much of the Amazon forest is resilient to seasonal and moderate drought, but this resilience can and has been exceeded with experimental and natural severe droughts, indicating a risk of carbon loss if drought increases with climate change."

The paper also noted that there had been extreme droughts and floods on the Tocantins and Araguaia basins, whose rivers drain the heavily deforested Cerado region.

"Where deforestation is widespread at local and regional scales, the dry season duration is lengthening and wet season discharge is increasing," it warned.

  • Hallo - 2012-01-19 00:12

    Climate change is already underway. Deal with it.

  • ludlowdj - 2012-01-19 11:55

    Climate change once again is a natural re-occurring cycle that cannot be stopped, it was here before man crawled out of the slime and will be here long after man has become extinct. Man cannot and will not ever be able to control it, our only means of exerting any control is through population control. simple mathematics indicating that at a steady 7% population increase per year, the earth will no longer be able to support human life within 100 years. Until government who has the most to gain from large populations admits that human survival as a species is not possible in the long term without enforced birth control and a net reduction in world population of at least 50%. Currently mans status on this planet most closely mimics the life cycle of a virus.

      Chumscrubber1 - 2012-01-19 21:23

      Very simple concept to understand, that we're breeding and thus consuming ourselves into oblivion. But I do believe the clever dudes who say our actions are contributing to more rapid climate change. Sure, a massive volcanic eruption can have a huge impact, but our damage to the environment simply accelerates our demise. Perhaps our collapse will just be part of a cycle, but I'd like to do what I can to slow down the inevitable in the meantime. Luckily I did not bring children onto this planet given the attitude of most adult humans today.

  • Getafix - 2012-01-19 23:32

    ya, 60 billion people dont have any affect on the environment, We have infinite air to breath, so keep pumping out cheap stuff that breaks, u will make more money at the end of the day. Turn those trees into cheap chip board. Marijuana grow 1000 times faster than a forest does, and can create the same stuff. What are the people in charge smoking?

  • Douglas - 2012-04-18 17:12

    "...the biomass of the Amazon contains a whopping 100bn tons of carbon - the equivalent of more than 10 years of global fossil-fuel emissions." Not quite. We actually produce around 30 billion tons of CO2 per year, making it only about 3 years' worth.

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