Drought worsens carbon dioxide levels

November 28th, 2007 - 4:28 pm ICT by admin  

Washington, Nov 28 (ANI): Government scientists have found that droughts dont just lead to parched land, but also exacerbate rising carbon dioxide levels.

It was found that in North America alone, human activity, from driving cars to generating power in factories, releases about two billion tons (1.85 billion metric tons) of carbon in the form of carbon dioxide every year.

Researchers have estimated that natural carbon sinks such as forests, grasslands, crops and soil absorb about one-third of those emissions.
However, droughts seem to hamper the ability of these sinks to suck up the greenhouse gas.

CarbonTracker, a new measurement system introduced by the National Oceanic and Atmospheric Administration, has provided researchers with weekly observations of carbon dioxide exchange from 2000 to 2005.

The data revealed that in 2002, when North America experienced one of the largest droughts in more than a century, the amount of carbon taken up by vegetation and soil plunged from 716 million tons to 363 million tons.

“Scientists often look at the role of greenhouse gases in producing climate extremes,” said lead author Wouter Peters, affiliated with Wageninen University and Research Center in The Netherlands.

“Here we show the reverse is also true. Climate extremes can have a major effect on the amount of carbon dioxide in Earths atmosphere,” Peters added.

Drought and other variations in a region’s climate can change temperatures, rainfall, soil moisture and even the length of the growing season in that region. If less rainfalls and soil moisture drops, plants may wither and die and so take up less carbon dioxide.

CarbonTracker showed that the connection between drought and increased carbon dioxide levels isn’t unique to North America; the widespread drought and heat wave that struck Europe in 2003 left more than 500 million extra tons of carbon dioxide in the atmosphere that year.

This problem could have consequences for efforts aimed at reducing greenhouse gas emissions.

“Disruptions to natural carbon uptake can have enormous environmental and economic effects, possibly even erasing efforts to reduce fossil fuel emissions in a given year,” Peters said.
The study is published in the Nov. 26 issue of the journal Proceedings of the National Academy of Sciences. (ANI)

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