Last year, the Amazon rainforest experienced the worst drought on record, reducing normally flowing rivers to sun-baked stretches of dried mud and pushing the fragile ecosystem to the brink. And even more troubling than the crippling drought itself was the notion that human caused global warming was a contributing factor, and that without reductions in CO2 emissions, such extended dry seasons would become common in the future. But now, according to a recent study, the outlook for the world's largest rainforest may be even more dire still. As a result of 2010's Amazon drought, experts say, some 1.8 billion tons of carbon dioxide was released into the atmosphere -- more than is produced by India's entire population in a years.Using a carbon cycle simulation model, NASA researcher Christopher Potter applied data gathered from last year's Amazon drought, namely measures of the forest's 'greenness' levels which serve as an indicator of the plants' photosynthetic efficiency, to assess what impact the lack of rainfall had on carbon dioxide emissions, and the findings were troubling. While drought is largely considered a 'natural' disaster, researchers suspect that the effects of global climate change may have contributed to its severity -- which resulted in a greater release of CO2 than did deforestation in the Amazon over the same period.
The study, which was printed in the journal Environmental Research Letters cites fragmentation of forest cover from Amazon deforestation as one cause of reduced precipitation in the region as well -- which experts warn could lead to a vicious cycle whereby forests are unable to fully regenerate, exacerbating the initial causes of drought.
A report from Mongabay.com paints a worrisome future for the 'lungs of the planet':
Using simulation models that account for the impact of increased atmospheric carbon dioxide concentrations on temperature and precipitation in the region, scientists at the Hadley Center for Climate Prediction and Research in the UK have forecast significant "die-back" of the Amazon rain forest by mid-century and a virtual collapse of the ecosystem by 2100.
Meanwhile Dan Nepstad, a scientist at the Instituto de Pesquisa Ambiental da Amazônia (IPAM), has estimated that as much as 55 percent of Amazon forests could be "cleared, logged, damaged by drought, or burned" in the next 20 years should deforestation, forest fires, and climate trends continue apace.
For a region so vast and so seemingly immovable as the Amazon rainforest, it is difficult to imagine that human activity could have such an impact on its overall health. But while the potential for human activity in the negative is understood with more clarity each passing year, the time is nye to test the positive.
(Read more at Mongabay.com)