Global warming encourages tree growth but dries up wetlands, studies show
Longer growing seasons and higher concentrations of CO2 may encourage faster growth rates in trees, according to a 22-year scientific study of mixed hardwoods in the eastern United States. During the study average temperatures increased by 0.3 degrees while the growing season was extended by 7.8 days. Furthermore, the CO2 concentration in the forest air went up 12%.
Higher concentrations of carbon dioxide and extended growing seasons could be favourable for agriculture in some parts of the world, mainly in the northern hemisphere. The study in Maryland suggests that the extra growth in trees could help to act as a more efficient carbon “sink”, which could offset the carbon dioxide being added to the atmosphere by the burning of fossil fuels.
These results were unexpected by scientists, but the conclusions – based on 250,000 measurements since 1987 carried out by the Smithsonian Environmental Research Center (SERC) in Maryland – are drawn from exhaustive research.
That’s the good news concerning northern forests and global warming as reported in The Independent. But a similar story by the AFP gives a wider scenario, including some bad results the rising temperatures might bring.
If temperatures rise by four degrees Celsius, parts of the North American prairie will become too dry for waterfowl and other parts will have too few functional wetlands and nesting habitat to support historical levels of wetland species, W. Carter Johnson, one of the authors of the study, said.
Another recently published study by the United States Geological Survey and South Dakota State University suggests that climate change may dry up many of North America’s wetlands. The study found that wetlands – important breeding grounds for duck, waterfowl and amphibians – are more vulnerable to climate change than previously believed.
by Graham Land
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