The global rise in temperatures spurred by the intensifying impact of climate change may be stunting the growth of rainforest trees — disrupting their ability to store carbon dioxide — according to a new study. Kenneth Feeley, a professor at Harvard University, and his colleagues found that large numbers of plant species in Malaysia and Panama — as many as 95% and 71% of species, respectively — showed significant decreases in their growth rates over a period of 24 years.
Over the study period, the researchers measured steady rises in daily minimum temperatures and in cloud cover — in one case, the minimum nightly temperature on Barro Colorado Island, Panama, increased by more than 1°C over the past 2 decades. They attribute the stunted growth rates to these warmer temperatures — theorizing that they may be slowing the process of photosynthesis, limiting the trees' ability to absorb carbon dioxide, and speeding up respiration, causing the trees to release more carbon dioxide. "We are only able to state that the slowing in growth that we observed is consistent with the hypothesis that increases in temperature will cause decreases in tree growth," explained Joseph Wright, a researcher at the Smithsonian Tropical Research Institute in Panama.If this trend persists, tropical forests will likely emit ever increasing amounts of carbon dioxide in the future — effectively raising atmospheric concentrations of greenhouse gases. Feeley and Wright hope that their research will now prompt other scientists to study tropical regions with similar climate patterns to see if this phenomenon is widespread. How this discovery will now shift the controversial debate on deforestation remains to be seen.
Via ::SciDev.Net: Tropical trees 'stunted by higher temperatures' (news website)
See also: ::Is Deforestation the Solution to Climate Change?, ::Biofuels Not Enough to Offset Damage Caused by Deforestation, ::Historical Perspective on Deforestation... and Chopsticks
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