Nature - Study Shows Increased CO2 Uptake By Plants Unlikely In Warmer World - May Become Net Source

Plants are unlikely to soak up more carbon dioxide from the air as the planet warms, research suggests. US scientists found that grassland took up less CO2 than usual for two years following temperatures that are now unusually hot, but may become common. The conclusion parallels a real-world finding from Europe's 2003 heatwave, when the continent's plant life became a net producer, not absorber, of CO2. The latest study is published in the scientific journal Nature.

Researchers extracted four intact segments of grassland, about 3 sq m in area and weighing about 12 tonnes each, from the prairies of Oklahoma, and placed them in special chambers at the Desert Research Institute (DRI) in Reno, Nevada. Conditions in the chambers, such as temperature, moisture and sunlight, could be precisely controlled.

Two of the four chambers were given a set of conditions mimicking what actually happens, on average, on the wild prairies. Temperatures rose and fell with days and nights and seasons, and "rainfall" was injected in a realistic pattern. The other two chambers received the same prescription with the exception that for a whole year, temperatures were always 4C higher.

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A lot of faith is being placed in some circles in the capacity of trees and plants to maintain absorption of CO2 as concentrations of the gas rise, or even to use the extra CO2 to grow faster and absorb more of it. It is one of the reasons behind the recent upsurge of interest in having western governments pay to protect tropical forests. But the DRI research is one of a number of pieces of evidence suggesting it will not always work. Some ecosystems might continue to absorb carbon dioxide, and perhaps increase the rate of absorption; others may react to warming by releasing the greenhouse gas.

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http://news.bbc.co.uk/2/hi/science/nature/7620921.stm

It wasn't long ago, and it wasn't some other place. It was here, and we had it in our grasp, and we ruined it with our greed and self-centeredness.

:cry: