Nav: Home

Retreat of the ice followed by millennia of methane release

May 13, 2016

Scientists have calculated that the present day ice sheets keep vast amounts of climate gas methane in check. Ice sheets are heavy and cold, providing pressure and temperatures that contain methane in form of ice-like substance called gas hydrate. If the ice sheets retreat the weight of the ice will be lifted from the ocean floor, the gas hydrates will be destabilised and the methane will be released.

Studies conducted at CAGE have previously shown that ice sheets and methane hydrates are closely connected, and that release of methane from the seafloor has followed the retreat of the Barents Sea ice sheet some 20 000 years ago. But is all such release of the potent climate gas bound to be catastrophic?

Not necessarily, according to a new study published in Nature Communications. It shows that the methane was indeed released as the ice sheets retreated. However the seepage did not occur in one major pulse, but over a period of 7000 to 10000 years following the initial release.

"The release was too slow to significantly impact the concentration of methane in the atmosphere." says researcher and project leader Aivo Lepland at Norwegian geological Survey (NGU) and CAGE.This may help explain why we have yet to discover a signal for such events in the various climate records of the past.

Radioactive material tells time

A new and groundbreaking method of dating carbonate rocks has been used to come to this conclusion. The seepage of methane over a long period of time created perfect conditions for formation of a special type of rock called authigenic carbonate crust. This could than be dated by scientists by a using a radiometric technique to measure natural decay of uranium to thorium.

"We have used carbonate crusts that form just below the sea-floor. They are a direct result of the oxidation of methane moving upwards though the sediment layers from deeper reservoirs. The chemical composition of the crust tells us that the source fluid was methane-rich, and the uranium-thorium dating tells us when this methane release happened." explains lead author of the study Antoine Cremiere, post.doc at NGU/CAGE.

Knowledge of the timescales of gas hydrate dissociation and subsequent methane release are critical in understanding the impact of marine gas hydrates on the ocean-atmosphere system, says Shyam Chand, researcher at NGU/CAGE.
-end-
Paper reference: Cremiere et. al. Timescales of methane seepage on the Norwegian margin following collapse of the Scandinavian Ice Sheet. Nature Communications 7, May 2016.

CAGE - Center for Arctic Gas Hydrate, Climate and Environment

Related Methane Articles:

Microbial fuel cell converts methane to electricity
Transporting methane from gas wellheads to market provides multiple opportunities for this greenhouse gas to leak into the atmosphere.
Methane seeps in the Canadian high Arctic
Cretaceous climate warming led to a significant methane release from the seafloor, indicating potential for similar destabilization of gas hydrates under modern global warming.
Methane emissions from trees
A new study from the University of Delaware is one of the first in the world to show that tree trunks in upland forests actually emit methane rather than store it, representing a new, previously unaccounted source of this powerful greenhouse gas.
Oil production releases more methane than previously thought
Emissions of methane and ethane from oil production have been substantially higher than previously estimated, particularly before 2005.
Bursts of methane may have warmed early Mars
The presence of water on ancient Mars is a paradox.
New method for quantifying methane emissions from manure management
The EU Commision requires Denmark to reduce drastically emissions of greenhouse gases from agriculture.
New 3-D printed polymer can convert methane to methanol
Lawrence Livermore National Laboratory scientists have combined biology and 3-D printing to create the first reactor that can continuously produce methanol from methane at room temperature and pressure.
Arctic Ocean methane does not reach the atmosphere
250 methane flares release the climate gas methane from the seabed and into the Arctic Ocean.
Long-sought methane production mechanism identified
Researchers have identified the mechanism by which bacteria create methane, a potent greenhouse gas.
Retreat of the ice followed by millennia of methane release
Methane was seeping from the seafloor for thousands of years following the retreat of the Barents Sea ice sheet, shows a groundbreaking new study in Nature Communications.

Related Methane Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Moving Forward
When the life you've built slips out of your grasp, you're often told it's best to move on. But is that true? Instead of forgetting the past, TED speakers describe how we can move forward with it. Guests include writers Nora McInerny and Suleika Jaouad, and human rights advocate Lindy Lou Isonhood.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...