'Unexpected': Arctic Ocean Methane Seeps Cool Water, Help Reduce Global Warming

Research off the coast of Norway's Svalbard archipelago has shed light on areas where methane gas bubbles up from the seafloor seeps. The surface water directly above the seeps absorbs twice as much carbon dioxide (CO2) as surrounding waters, which could mean that methane gas bubbles are helping slow down global warming.

The findings suggest that methane seeps in isolated spots in the Arctic could lessen global warming.

One of the researchers, Brett Thornton, a geochemist at Stockholm University, said that the results are totally "unexpected." 

"These findings challenge the popular assumption that methane seeps increase the global greenhouse gas burden," Mr. Thornton said.

Methane is a greenhouse gas that traps 30 times as much heat in the atmosphere as CO2_. However, little is known about the role of methane gas place in the global carbon cycle. 

Most methane gas that is found in the atmosphere comes from burning fossil fuels and bacteria feasting on decomposing litter.

Discovered: 200-plus #Arctic #lakes which bubble like jacuzzis from seeping #methane gas. Via https://t.co/5LC04zVgEo pic.twitter.com/S00yj85YTC

— EGU (@EuroGeosciences) 6 April 2017

​However, methane bubbles found in the ocean come from deep seeps, which are stored in crystal lattices of water called hydrates. When the hydrates melt due to changing temperatures and pressures, the methane is released and it can seep into the atmosphere above.

John Pohlman, biogeochemist from the US Geological Survey and one of the scientists who worked on the study, decided to look at how much the methane gas was close to the ocean surface. The scientists were surprised with how little methane they found. But the biggest surprise of all, according to the scientists, was that the surface water CO₂ levels dropped whenever their ship crossed a seep.

When they combined this data with the fact that water temperature had dropped, the lower CO2 levels was a sign of bottom water upwelling and photosynthesis.

Pohlman and his team conclude that the same physical forces that are pushing the methane bubbles up are also pumping nutrient-rich cold waters from the sea bed to the surface, fertilizing phytoplankton blooms that soak up CO2.

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An Arctic dawn

© Sputnik / Alexander Liskin

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The study uncovered that nearly 1900 times more CO2 is being absorbed than methane emitted, and according to Pohlman and his team this is a good consolation for those concerned about global warming.

However, the research still has some way to go, with the scientists  unsure if the findings apply to ocean seeps in other parts of the world.