Freshwater methane emission changes greenhouse gas equation

WASHINGTON - Greenhouse gas uptake by continents is less than previously thought because of methane emissions from freshwater areas, to newly released data by an international team of scientists.

John Downing of the Iowa State University concluded that methane release from inland waters is higher than previous estimates.

The study has indicated that methane gas release from freshwater areas changes the net absorption of greenhouse gases by natural continental environments, such as forests, by at least 25 percent.

The new study gives scientists a better understanding of the balance between carbon sequestration and greenhouse gas releases from fresh water bodies.

“Methane is a greenhouse gas that is more potent than carbon dioxide in the global change scenario.

“The bottom line is that we have uncovered an important accounting error in the global carbon budget. Acre for acre, lakes, ponds, rivers and streams are many times more active in carbon processing than seas or land surfaces, so they need to be included in global carbon budgets,” said Downing.

David Bastviken, principal author and professor in the department of water and environmental studies, at Linkoping University in Sweden, said small methane emissions from the surfaces of water bodies occur continuously.

“Greater emissions occur suddenly and with irregular timing, when methane bubbles from the sediment reach the atmosphere, and such fluxes have been difficult to measure,” said Bastviken.

The researchers studied methane fluxes from 474 freshwater areas and calculated emission based on new estimates of the global area covered by inland waters.

The findings were published in the journal Science. (ANI)