Melting Arctic Ice Causing More Methane Emissions
The melting of the Arctic ice cap is encouraging more natural emissions of methane — one of the most potent greenhouse gases driving climate change.
Researchers at Sweden’s Lund University worked with Dutch and American colleagues to find that the recent accelerated melt of sea ice around the North Pole is allowing the Arctic’s surface waters to absorb more heat and promote the growth of microorganisms in the adjacent tundra.
Those microbes in turn give off natural methane emissions that promote even further climate change and sea ice loss.
This feedback loop of warming and melting appears to have increased with virtually every new cycle over the past decade.
“While numerous studies have shown the effects of sea ice loss on the ocean, there are only a few that show how this oceanic change affects ecosystems on the surrounding land,” said study author Frans-Jan Parmentier.
The findings were published in the journal Geophysical Research Letters.
Microbes in recently thawed Arctic tundra are emitting the powerful greenhouse gas methane because of the greater summertime melt of the polar ice cap.
Newly Discovered Microbe in Melting Tundra
A microbe recently discovered in the melting Arctic permafrost appears to be releasing vast amounts of the greenhouse gas methane, possibly speeding up climate change.
Methanoflorens stordalenmirensis “breathes out methane like we breathe out carbon dioxide,” said lead author Carmody McCalley, a scientist at the Earth Systems Research Center at the University of New Hampshire.
Methane makes up only about 9 percent of all the greenhouse gases in the atmosphere, but it can store up to 21 times more heat than carbon dioxide.
Researchers say they hope the microbic discovery will help scientists improve their simulations of future climate by providing a more accurate picture of how thawing permafrost releases greenhouse gases.
An instrument measuring methane emissions from Methanoflorens stordalenmirensis in northern Sweden
Twice as Much Methane Escaping Arctic Seafloor
The Arctic methane time bomb is bigger than scientists once thought, according to a new study. About 17 teragrams of methane escapes each year from a broad, shallow underwater platform called the East Siberian Arctic Shelf.
Arctic Methane an ‘Economic Time Bomb’.
Increasing temperatures in the Arctic region are reducing sea ice cover and increasing the possibility of methane leaching from the sea bed. Scientists say that the release of large amounts of methane from thawing permafrost in the Arctic could have huge economic impacts for the world.
The researchers estimate that the climate effects of the release of this gas could cost $60 trillion (£39 trillion), roughly the size of the global economy in 2012. The impacts are most likely to be felt in developing countries they say. Scientists have had concerns about the impact of rising temperatures on permafrost for many years. Large amounts of methane are concentrated in the frozen Arctic tundra but are also found as semi-solid gas hydrates under the sea. Previous work has shown that the diminishing ice cover in the East Siberian sea is allowing the waters to warm and the methane to leach out. Scientists have found plumes of the gas up to a kilometre in diameter rising from these waters.
Methane is a powerful greenhouse gas, even though it lasts less than a decade in the atmosphere. the researchers examined the impact of the release of 50-gigatonnes of methane over a decade. They worked out that this would increase climate impacts such as flooding, sea level rise, damage to agriculture and human health to the tune of $60 trillion. “That’s an economic time bomb that at this stage has not been recognised on the world stage. We think its incredibly important for world leaders to really discuss what are the implications of this methane release and what could we indeed do about it to hopefully prevent the whole burst from happening.”
The researchers say their study is in marked contrast to other, more upbeat assessments of the economic benefits of warming in the Arctic region. It is thought that up to 30% of the world’s undiscovered gas and 13% of undiscovered oil lie in the waters. Transport companies are looking to send increasing numbers of ships through these fast melting seas. Investment in the Arctic could reach $100bn within ten years.
But according to the new work, these benefits would be a fraction of the likely costs of a large scale methane emission. The authors say a release of methane on this scale could bring forward the date when global temperatures increase by 2C by between 15 and 35 years. New research suggests that permafrost is also melting in Antarctica. Scientists have found that ground ice in the McMurdo Dry Valley Regions has accelerated consistently between 2001 and 2012, rising to about ten times the historical average. The researchers say that rising temperatures do not account for this increased melting but is due to an increase in sunlight caused by changes in weather patterns.
“We are looking at a big effect, a possibly catastrophic effect on global climate that’s a consequence of this extremely fast sea ice retreat that’s been happening in recent years.” Some scientists have cautioned that not enough is known about the likelihood of such a rapid release of methane. Even though it has been detected for a number of years, it has as yet not been found in the atmosphere in large amounts. But the evidence is growing. “We are seeing increasing methane in the atmosphere. When you look at satellite imagery, for instance the Metop satellite, that’s gone up significantly in the last three years and the place where the increase is happening most is over the Arctic.”
The authors say that the impacts of the extra methane would be felt most in developing countries which are more vulnerable to rising waters, flooding and the agricultural and health impacts of rising temperatures.