Methane’s Contribution to Global Warming Is Worse than You Thought

It seems we've been "fudging the numbers" in a sense, when comparing the global warming potential of methane to CO2. When global warming potential (GWP) of a gas is calculated, a time frame is assumed. The IPCC decided to use a 100 year time frame.

With a 100 year time frame methane heats up the planet 21 times as much as CO2. The problem with that assumption is that we don't have 100 years. A 20 year time frame would be much more realistic, given the urgency of climate crisis. With a 20 year time frame...

... any CH4 released today is at least 56 times more heat-trapping than a molecule of C02 also released today. And because of the way it reacts in the atmosphere, the number is probably even higher, according to research conducted by  Drew Shindell , a scientist at NASA’s Goddard Space Center. [emphasis mine]


What if we were to use the IPCC’s 20-year comparison instead of its 100-year comparison? For starters, it would force us to get much more serious about tackling  the sources of methane emissions. Here in the US, the top methane sources are the decomposition of wastes in landfills, agriculture (from ruminant digestion), and leaks from natural gas drilling and transmission. A new emphasis on methane would require us to get smarter about capturing methane at landfills, reduce the market incentives that encourage Americans’ meat-heavy diets, and ensure that methane isn’t leaking from fracking operations.

But beyond the policy specifics, adopting the 20-year global warming potential comparisons would be useful for changing how we think about climate change.

And we appear to be approaching some irrevocable tipping points that will create powerful negative feedback loops, the most worrisome being  the release of methane  stores at the bottom of the ocean and locked into sub-Arctic permafrost.

Image from Arctic Methane Release Tipping Point Diagram
With 56 times as much warming as CO2 in mind, we'd take this feedback more seriously.

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Replies to This Discussion

In addition to the methane spike over Antarctica there was

... a methane reading of 2475 ppb was recorded on April 26, 2013, appearing to originate from the Himalayan Plateau ...

This article also connects the albedo decline in the Arctic, due to melting sea ice, to declining atmospheric hydroxyl concentrations.

Decrease of surface reflectivity results in increases in absorption of energy from sunlight and decreases in shortwave radiation in the atmosphere. The latter results in lower photo-dissociation rates of tropospheric gases. Photo-dissociation of the ozone molecule is the major process that leads to the production of OH (hydroxyl radical), the main oxidizing (i.e., cleansing) gas species in the troposphere. A 2009 NASA study projects this to lead to a decrease in OH concentrations and a weakening of the oxidizing capacity of the Arctic troposphere, further increasing the vulnerability of the Arctic to warming in case of additional methane releases.

Is the permafrost's integrity breaking down?

In sum, the half-life of methane in the atmosphere depends upon available hydroxyl ions to break it down. The oft cited values of methane half-life were calculated in non polar latitudes where hydroxyl is far more plentiful. At the poles the hydroxyI concentration is normally much lower.  I lost the link to the news article that mentioned that hydroxyl concentrations in the Arctic had already begun to decline from their low level. Two factors are in play to depress hydroxyl concentrations even more, increasing methane release will consume it, and according to this article albedo decline will lead to less being produced. The problem is that when hydroxyl is depleted at the poles, emitted methane will hang around much much longer, to further amplify localized warming there.

Horrific amounts of methane over Laptev Sea

The Laptev Sea is part of the Eastern Siberian Arctic Shelf in the Arctic Ocean.

Harold Hensel recently posted the image below with the huge areas solidly colored red indicating release of horrific amounts of methane.

Red dominates indicates emissions of 1950 ppb and higher.

To put the above image into context,

Arctic Seafloor Methane Releases Double Previous Estimates

The seafloor off the coast of Northern Siberia is releasing more than twice the amount of methane as previously estimated, according to new research results published in the Nov. 24 edition of the journal Nature Geoscience.

The East Siberian Arctic Shelf is venting at least 17 teragrams of the methane into the atmosphere each year. A teragram is equal to 1 million tons.

"It is now on par with the methane being released from the arctic tundra, which is considered to be one of the major sources of methane in the Northern Hemisphere,"...

The warming has created conditions that allow the subsea methane to escape in much greater amounts than their earlier models estimated. Frequent storms in the area hasten its release into the atmosphere, much in the same way stirring a soda releases the carbonation more quickly.

The East Siberian Arctic Shelf is ... more than three times as large as the nearby Siberian wetlands, which have been considered the primary Northern Hemisphere source of atmospheric methane. [emphasis mine]


On the other hand,

At the same time, she downplayed tying the research to the methane bomb theory espoused earlier this year, saying there’s not enough evidence to make that connection.

David Archer, a carbon cycle expert at the University of Chicago agreed. “In order to ignite an Arctic methane bomb you would have to ramp up (emissions) by a factor of 10 or 100 very quickly, and there's no evidence or any proposed mechanism that could make it blow up that quickly,”... [emphasis mine]

Arctic Storms, Warming Mean More Methane Released

I realized that 1950 ppb of Methane doesn't mean much, out of context. Here's some background.

According to the U.S. Department of Energy, Office of Science, as of February 2013, methane levels in the atmosphere are measured at 1,874 ppb (parts per billion). This level, in an historical context, is more than twice as high as any time since 400,000 years before the industrial revolution. In the past, methane has ranged between 300-400 ppb during glacial periods and 600-700 ppb during warm interglacial periods. [emphasis mine]

The Inevitability of Radical Climate Change

More scary Siberian Ice Shelf info.

"We have proven that the current state of subsea permafrost is incomparably closer to the thaw point than terrestrial permafrost, and that modern warming does contribute to warming the subsea permafrost," says Shakhova. Increasing storminess in the Arctic, predicted by some climate models, would speed up the release of methane, she says. [emphasis mine]

Arctic storms speed up release of methane plumes

The earlier articles

  • didn't mention that subsea permafrost was much closer to thawing than terrestrial permafrost, and
  • while they connected Arctic storms to faster methane release, they failed to mention that Climate Destabilization might increase those storms.

As atmospheric methane concentrations increase, the global warming potential of methane in the air will also increase, according to new research. Any source elevating atmospheric methane concentrations will also raise the Global Warming Potential of all previously emitted methane remaining in the atmosphere.

Here we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical composition of the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 ... above current emissions, the indirect contributions to RF would be about 250% ... of the RF that can be attributed to directly emitted methane alone.

In particular, the impact of CH4 is enhanced through increase of its lifetime, and of atmospheric abundances of ozone, stratospheric water vapor, and CO2 as a result of atmospheric chemical processes. [emphasis mine]

Strong atmospheric chemistry feedback to climate warming from Arcti...

Above is an abstract, the full paper is behind a paywall.

This is likely not in addition to hydroxyl depletion mentioned in an earlier reply. Surely they include abundance of hydroxyl in the overall chemistry they examined.

A methane venting event the size of the continental US happened this February in Antarctica. It didn't even happen along the coast, but right over the central ice dome. Mechanism unknown. Surprise, another unknown unknown. *groan*

No time to watch the slow moving video? Here's a screen capture.

Apparently this Antarctic methane will circulate globally within a year.

David Archer at RealClimate (in reply to a comment #6) claims that

... the mixing time for the atmosphere is short, about a year for exchange between the hemispheres and much shorter for mixing along latitude circles, shorter than the thermal equilibration time from rising greenhouse gases. So in general the Earth warms and cools as a whole from GHG concentrations.

This methane issue stinks.

It's all because there are too many people on the planet. It's yet another symptom of overpopulation.

The problem is no-one has a solution. If everyone 'did their best' it still wouldn't be enough. So go ahead and use all the disposable razor blades and free plastic shopping bags you want because we're all fucked anyway.

Oh, and another thing, don't discuss the issue. It will upset people.

People need to be upset.

Ruth shared this article elsewhere: "Climate Change Needs the Politics of the Impossible", which is actually guardedly optimistic!

One reason for hopefulness, even for measured optimism...: extraordinary politics is a real thing, not just an idle wish.

Consider the end of slavery—not in the U.S., but in the British Empire, which abolished the practice thirty years before the Emancipation Proclamation, by an act of Parliament, with compensation to slaveholders.  The economic cost was huge.  For decades, historians assumed it must have been a subterfuge for someone’s economic benefit—otherwise, how would such a thing be possible?  But the historians’ view these days is that British emancipation was, in fact, a wildly expensive and disruptive moral commitment, executed through extraordinary politics.  The powerful thing about this example is its scale: the global economy of the British Empire was nearly as entwined with slavery as ours is with the fossil-fuel economy.  The change wasn’t just costly: it pulled some institutions up by their roots.  If that never happened, we’d really be out of reasons for hope on climate change.  But sometimes it does.

We should learn to look at climate change simultaneously through two very different lenses.  Keep one eye on the scientists’ reports... and the Silicon Valley technologists’ innovations....  But cast the other on the activist kids who don’t know enough to realize they can’t win—the ones getting arrested outside the White House... and pressing universities and pension funds to divest from fossil fuels....

It’s easy—ridiculously easy—to show that the activists shouldn’t expect to win....  But that is true at the beginning of every episode of extraordinary politics.  That why histories of abolition, the civil rights movement, even environmentalism, don’t begin with people who are powerful, realistic, or even normal.  They begin with people who don’t know better, and who find the world they are born into intolerable....

Our current normal is built out of principles that used to be considered impossible—gender equality, racial equality, democracy—and became common sense long after some people were too unrealistic to give up on them.... Today’s climate activists are aiming at the same kind of change: to help see, and feel, a disrupted and dangerous world as their problem, their responsibility, something they love enough not to give up on it.

(Read the whole thing!)

Climate Change Needs the Politics of the Impossible




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