Its emissions add to those produced by the tundra

Apr 23, 2012 07:12 GMT  ·  By
Surprising levels of the potent greenhouse gas methane were found coming from cracks in the Arctic sea ice
   Surprising levels of the potent greenhouse gas methane were found coming from cracks in the Arctic sea ice

The results of a new scientific investigation suggest that another important source of methane may exist in the Arctic, in addition to tundra and permafrost soils. The ocean itself may be producing important amounts of methane, an extremely potent greenhouse gas.

Experts estimate that it can heat up the atmosphere 300 times more efficiently than carbon dioxide can. Arctic soils contain massive amounts of decaying organic matter, which produce large quantities of CH4.

As the effects of global warming are starting to be felt near the North Pole, more and more of these soils are beginning to thaw, releasing their carbon contents into the atmosphere. The amount of methane present in Arctic soils is simply massive, enough to produce a runaway global warming effect.

What the new investigation found was that the ocean itself was a potent source of CH4. The multi-institutional team that reached these conclusions was coordinated by Eric Kort, an expert with the NASA Jet Propulsion Laboratory (JPL), in Pasadena, California.

He holds an appointment as a postdoctoral scholar at JPL, and is affiliated with the Keck Institute of Space Studies at the California Institute of Technology (Caltech), in Pasadena, which manages the lab. His investigation was part of the HIAPER Pole-to-Pole Observations (HIPPO) airborne campaign.

Between 2009 and 2010, HIPPO conducted five flights over the Arctic. During these sorties, the expert and his team were able to detect elevated methane concentrations in the air, as they were flying over the Beaufort and Chukchi Seas.

Methane levels were around 0.5 percent higher than the background average, the group reports. At the same location, researchers could not find any carbon monoxide in the atmosphere, as they were originally expecting to see.

Cracks in Arctic sea ice and areas of partial sea ice cover are responsible for this methane release, the investigators eventually discovered. Seawater is exposed through these cracks, which means that the ocean can therefore interact with the atmosphere.

Methane in the surface water then escapes into the air, contributing to accelerating global warming at and around the North Pole. The team says that areas of the ocean that were covered in solid ice displayed no elevated methane concentrations.

“While the methane levels we detected weren't particularly large, the potential source region, the Arctic Ocean, is vast, so our finding could represent a noticeable new global source of methane,”Kort says.

“As Arctic sea ice cover continues to decline in a warming climate, this source of methane may well increase. It's important that we recognize the potential contribution from this source of methane to avoid falsely interpreting any changes observed in Arctic methane levels in the future,” he adds.

The new study is published in the April 22 issue of the top journal Nature Geoscience.