Nature.com – August 10, 2007
The common thinking was that as global warming increased, rainforests would grow faster and would naturally moderate the effect.
This study suggests differently. This study notices that 2 rainforests actually slowed down their average growth as the temperature in that area of the world increased. While the scientists validly point out that there may be many other factors or combinations of factors to this outcome, it is concerning.
It is also concerning that the various climate models do not adequately model this phenomenon. Once again we find that we still do not have a solid understanding of our environment and we need to expand our investment in this science.
Global warming could cut the rate at which trees in tropical rainforests grow by as much as half, according to more than two decades’ worth of data from forests in Panama and Malaysia. The effect ? so far largely overlooked by climate modellers ? could severely erode or even remove the ability of tropical rainforests to remove carbon dioxide from the air as they grow.
If other rainforests follow suit as world temperatures rise, important carbon stores such as the pristine old-growth forests of the Amazon could conceivably stop storing as much carbon, says Ken Feeley of Harvard University’s Arnold Arboretum in Boston, who presented the research at the annual meeting of the Ecological Society of America in San Jose, California.
The amount of carbon that a forest stores depends on the balance between the rate at which it draws carbon dioxide from the atmosphere through photosynthesis and the rate at which it gives carbon dioxide back through respiration. In carbon sinks, which are mostly found at high latitudes, photosynthesis outstrips respiration and the amount of carbon stored increases. In general, tropical forests are today thought to act as stable stores of carbon, with their photosynthetic input and their respiratory output more or less in balance.
Some scientists and environmentalists have suggested that, given the way carbon dioxide spurs plant growth, tropical forests could in time come to act as a sink, offsetting some of the man-made carbon dioxide build-up.