CO2 as fertilizer

Rising Carbon Dioxide Levels Causing Desert ‘Greening’

Written by John O’Sullivan
Rise in the level of carbon dioxide in the air is causing desert “greening” and has increased foliage cover by 11 percent reports Sam Lehman in hngn.com (July 9, 2013)

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Up until now the negative aspects of rising levels of carbon dioxide have been highlighted in almost all studies conducted on this matter. A new study, based on satellite observations, CSIRO, in collaboration with the Australian National University (ANU) reported that the rising levels of carbon dioxide have caused deserts to start greening and  increased foliage cover by 11 percent from 1982-2010 across parts of the arid areas studied in Australia, North America, the Middle East and Africa.

“In Australia, our native vegetation is superbly adapted to surviving in arid environments and it consequently uses water very efficiently,” CSIRO research scientist, Dr Randall Donohue, said in a press statement. “Australian vegetation seems quite sensitive to CO2 fertilization.”

While scientists have speculated that carbon dioxide may be causing such changes, this is the first study that confirmed the effects. For the study, researchers used a mathematical modeling together with satellite data adjusted to take out the observed effects of other influences such as rainfall, air temperature, the amount of light and land-use changes.

Elevated carbon dioxide levels affect the photosynthesis process of a leaf causing it to consume less water to convert sunlight into sugar. This leads to plants in arid environments increasing their number of leaves. This increase in the number of leaves can be easily detected by satellites since foliage cover is less in arid areas when compared to wet locations.

“On the face of it, elevated CO2 boosting the foliage in dry country is good news and could assist forestry and agriculture in such areas; however there will be secondary effects that are likely to influence water availability, the carbon cycle, fire regimes and biodiversity, for example,” Dr Donohue concluded. “Ongoing research is required if we are to fully comprehend the potential extent and severity of such secondary effects.”

 

The findings of the study were published in the journal US Geophysical Research Letters.



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