NEW YORK: Global warming could cut the rate at which trees in tropical rainforests grow by as much as half, a new study based on more two decades of data from forests in Panama and Malaysia shows.
The effects, so far largely overlooked by climate modellers, Nature magazine said, could severely erode or even remove the ability of tropical rainforests to remove carbon dioxide from the air as they grow.
The study, it said, shows that rising average temperatures have reduced growth rates by up to 50 per cent in the two rainforests, which have both experienced climate warming above the world average over the past few decades. The trend is shown by data stretching back to 1981 collected from hundreds of thousands of individual trees, Nature said.
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, 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, was quoted as saying.
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.