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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