Thursday, August 9, 2012

Methane emissions mustn't be overlooked

Carbon dioxide (CO2) is the greenhouse gas mostly responsible for global warming phenomenon but the role of methane mustn't be overlooked, particularly because methane is much more potent greenhouse gas compared to CO2 (methane is 25 times more effective than CO2  at trapping heat in the atmosphere).

The scientists have calculated that the atmospheric methane concentration has increased by about 150% since 1750, and the methane emissions continue to grow, often from underappreciated sources such as dams and diseased trees.

According to a latest study by the Washington State University the role of water reservoirs in greenhouse gas emissions has been seriously overlooked because methane emissions jump considerably during dam drawdowns.

This is especially the case during hot summer months, when warmer temperatures and low oxygen conditions in bottom waters stimulate the growth of microbes that produce methane. The U.S. scientists have discovered that „methane emissions jumped 20-fold when the water level was drawn down.“

Since U.S. alone has around 80,000 dams, effectively managing these dams could decrease the levels of methane that gets released to the atmosphere.

The other study done by Yale scientists has examined the role of diseased trees (fungal rot of timber trees) in methane emissions. They believe that diseased trees in forests could become a significant source of methane emissions in years to come.

They have sampled sixty diseased trees at Yale Myers Forest in northeastern Connecticut and discovered that these trees had concentrations of methane that were as high as 80,000 times of normal air.
The predicted methane emission rate from this site at the Yale forest is approximately the same as is the burning of 40 gallons of gasoline per hectare of forest per year.

Xuhui Lee, a co-author of the study, said that "if we extrapolate these findings to forests globally, the methane produced in trees represents 10 percent of global emissions."

What this means is that though the carbon dioxide still remains the major culprit for ongoing climate change issue, we mustn't forget about other greenhouse gases, especially the most potent ones, such as methane.

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