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One of the most alarming aspects of climate change is the existence of positive feedback loops. For example, as polar ice melts, less sunlight is reflected back into space, thus heating up the ocean and causing more ice to melt. Rinse and repeat. Another one: warming causes the permafrost in the Siberian tundra to melt, releasing CO2 into the atmosphere, thus warming the earth and causing yet more tundra to melt.He quotes this Washington Monthly piece:
The world's forests are an enormous carbon sink, meaning they absorb massive quantities of carbon dioxide, through the processes of photosynthesis and respiration. In normal years the Amazon alone absorbs three billion tons of carbon, more than twice the quantity human beings produce by burning fossil fuels. But during the 2005 drought, this process was reversed, and the Amazon gave off two billion tons of carbon instead, creating an additional five billion tons of heat-trapping gases in the atmosphere. That's more than the total annual emissions of Europe and Japan combined.The drought was not evenly spread across the vast expanses of the Amazon, but in the worst affected areas there was severe dieback. Some trees stopped growing, others lost their leaves, and many of the fastest-growing trees and creepers died altogether. Perhaps more surprising, comparing exact measurements of tree diameter, wood density, and biomass against measurements taken in earlier years, Phillips and his colleagues found that even in places that seemed to emerge relatively unscathed--where the forest looked no different to the naked eye--there had been a loss of biomass. Rainforests, it seems, are more sensitive to drought than was previously understood.
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