An upside to climate change? The issue has been blamed for many problems, including more acidic oceans and rising pollen counts, but a study released Friday suggests a benefit: Arid regions are getting greener.
Satellite data since the early 1980s have shown a flourishing of foliage worldwide, and scientists have suspected this change may be due partly to the increase in atmospheric carbon dioxide, a heat-trapping greenhouse gas emitted by the burning of fossil fuels..
Turns out, they were right because of CO²’s “fertilization effect,” according to a team of scientists led by Randall Donohue of the Commonwealth Scientific and Industrial Research Organization in Canberra, Australia.
Their mathematical model predicted a foliage increase of 5 to 10 percent, based on the 14 percent increase in atmospheric CO² from 1982 to 2010, for the regions they studied: the southwestern corner of North America, Australia’s outback, the Middle East and some parts of Africa.
What actually happened? Satellites showed an 11 percent increase in foliage after adjusting data for precipitation.
Donohue said previous research linked the rise in global vegetation to “fairly obvious climatic variables,” such as rising temperatures in normally cold places or rising rainfall in typically dry areas. He said his team is the first to show a CO² link.
“If elevated CO² causes the water use of individual leaves to drop, plants will respond by increasing their total numbers of leaves,” Donohue said in announcing the findings. The study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.
Donohue said the “fertilization effect” could also alter the types of vegetation in dry areas. “Trees are reinvading grass lands, and this could quite possibly be related to the CO² effect,” he said. “Long-lived woody plants are deep rooted and are likely to benefit more than grasses from an increase in CO².”
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