Amazon drought highlights impact of global warming

Stalin

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Recent scientific research point has pointed to serious implications arising from the record Amazon rain forest drought that took place last year. A previous drought in 2005 was regarded as a rare one in a 100-year event, associated with an unusual rise of Atlantic Ocean sea temperatures. However a detailed examination of recent satellite rainfall data compared to similar data over the last decade by a UK-US-Brazilian team showed that the recent drought was in fact more extensive than the 2005 episode [1]. Whereas the 2005 drought was spread over an area of two million sq. km., the 2010 drought extended over three million sq. km.

This is not just a devastating event for the people of Brazil living in the forest region or the Amazon basin. What is of global concern is that the rain forest in a drought period, instead of acting as a net absorber of carbon dioxide and absorbing some of the increase in human-based emissions, actually emits the greenhouse gas on an even bigger scale due to trees dying and rotting.

Using satellite data as well as extensive studies on the ground the research team calculated the additional amount of carbon dioxide produced as a result of the 2005 drought at five billion tonnes (compared, for example, to 5.4 billion tonnes emitted by the US in 2009). Normally the forest has been absorbing carbon dioxide at a rate of about 1.5 billion tonnes a year. Using their satellite data the team estimate the 2010 drought could have resulted in a net production of up to 8 billion tonnes of greenhouse gas.

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The leading scientist of the team, Dr Simon Lewis, from the University of Leeds UK, said: “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.”

This refers to the possibility, shown up in some of the complex computer models of the earth’s climate, that a “feedback” effect could result in recurring Amazon droughts and higher carbon emissions. Lewis cautioned that there was still considerable uncertainty about what was happening, but warned, “current emissions pathways risk playing Russian roulette with the world’s largest rainforest.”

Dr Lewis featured in the wave of climate change denial in the capitalist media in the run-up to the Copenhagen summit in December 2009. A particularly scurrilous attack was mounted in the UK Sunday Times, part of a world campaign in the Murdoch press, trawling through the report of the UN Intergovernmental Panel on Climate Change (IPCC) for alleged scientific errors.

In what was called the “Amazongate” scandal, the newspaper alleged that a claim that 40 percent of the rain forest could be affected by climate change was spurious and cited the reference given in the IPCC report to the campaigning NGO, the World Wildlife Fund. In fact the WWF had based their figure on the work of Dr Lewis’s team, which the IPCC should have cited. Lewis sent a collection of peer-reviewed scientific papers to the Sunday Times and it was forced to issue an apology.

http://www.wsws.org/articles/2011/feb2011/warm-f11.shtml

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