A new study supported by the National Science Foundation and the US Department of Energy has concluded that forests and other terrestrial ecosystems in the contiguous United States of America can sequester up to 40 percent of the nation’s fossil fuel carbon emissions.
That is, unless there’s a drought or other major disturbance.
The figure is actually higher than had previously been estimated, but widespread droughts such as those which took place in 2002 and 2006 can do serious harm to the sequestration of carbon emissions.
The researchers studied the carbon budget in the US between 2001 and 2006, a period of time which contained a number of catastrophic and unusual events, including two large scale droughts, the Biscuit Fire in southwest Oregon, and Hurricane Katrina.
The data was gathered from satellite measurements and dozens of environmental observations sites in the AmeriFlux network, including data which had previously not been included in similar studies.
“With this data it appears that our forests and other vegetation can sequester as much as 40 percent of the carbon emissions in the lower 48 states,” said Beverly Law, a co-author of the study, professor in the Department of Forest Ecosystems and Society at Oregon State University, and science team chair of the AmeriFlux network.
“That’s substantially higher than some previous estimates, which indicated these ecosystems could take up the equivalent of only about 30 percent of emissions or less,” Law said. “There’s still some uncertainty in these data, but it does appear that the terrestrial carbon sink is higher than believed in earlier studies.”
But with the good news comes the revelations provided by the unnatural natural events which took place during their studies timeframe.
“With climate change, we may get more extreme or frequent weather events in the future than we had before,” Law said. “About half of the United States was affected by the major droughts in 2002 and 2006, which were unusually severe in their spatial extent and severity. And we’re now learning that this can have significant effects on the amount of carbon sequestered in a given year.”
“Our results show that U.S. ecosystems play an important role in slowing down the buildup of carbon dioxide in the atmosphere,” the researchers wrote in their conclusion. “The dominant sources of the recent interannual variation included extreme climate events (e.g., drought) and disturbances (e.g., wildfires, hurricanes).”
Source: Oregon State University
Image Source: CIAT International Center for Tropical Agriculture