Siberian Methane Thawing Rapidly

[Admiral Valdemar]

A Storehouse of Greenhouse Gases Is Opening in Siberia

By Volker Mrasek

Researchers have found alarming evidence that the frozen Arctic floor has started to thaw and release long-stored methane gas. The results could be a catastrophic warming of the earth, since methane is a far more potent greenhouse gas than carbon dioxide. But can the methane also be used as fuel?

It's always been a disturbing what-if scenario for climate researchers: Gas hydrates stored in the Arctic ocean floor -- hard clumps of ice and methane, conserved by freezing temperatures and high pressure -- could grow unstable and release massive amounts of methane into the atmosphere. Since methane is a potent greenhouse gas, more worrisome than carbon dioxide, the result would be a drastic acceleration of global warming. Until now this idea was mostly academic; scientists had warned that such a thing could happen. Now it seems more likely that it will.

Russian polar scientists have strong evidence that the first stages of melting are underway. They've studied largest shelf sea in the world, off the coast of Siberia, where the Asian continental shelf stretches across an underwater area six times the size of Germany, before falling off gently into the Arctic Ocean. The scientists are presenting their data from this remote, thinly-investigated region at the annual conference of the European Geosciences Union this week in Vienna.

In the permafrost bottom of the 200-meter-deep sea, enormous stores of gas hydrates lie dormant in mighty frozen layers of sediment. The carbon content of the ice-and-methane mixture here is estimated at 540 billion tons. "This submarine hydrate was considered stable until now," says the Russian biogeochemist Natalia Shakhova, currently a guest scientist at the University of Alaska in Fairbanks who is also a member of the Pacific Institute of Geography at the Russian Academy of Sciences in Vladivostok.

The permafrost has grown porous, says Shakhova, and already the shelf sea has become "a source of methane passing into the atmosphere." The Russian scientists have estimated what might happen when this Siberian permafrost-seal thaws completely and all the stored gas escapes. They believe the methane content of the planet's atmosphere would increase twelvefold. "The result would be catastrophic global warming," say the scientists. The greenhouse-gas potential of methane is 20 times that of carbon dioxide, as measured by the effects of a single molecule.

Shakhova and her colleagues gathered evidence for the loss of rigor in the frozen sea floor in a measuring campaign during the Siberian summer. The seawater proved to be "highly oversaturated with solute methane," reports Shakhova. In the air over the sea, greenhouse-gas content was measured in some places at five times normal values. "In helicopter flights over the delta of the Lena River, higher methane concentrations have been measured at altitudes as high as 1,800 meters," she says.

The methane climate bomb is also ticking on land: A few years ago researchers noticed higher concentrations of methane in northern Siberia. The Siberian permafrost is known as one of the tipping points for the earth's climate, since the potent greenhouse gas develops wherever microorganisms decompose the huge masses of organic material from warmer eras that has been frozen here for thousands of years.

"A Wake-Up Call for Science"

Data from offshore drilling in the region, studied by experts at the Alfred Wegener Institute for Polar and Marine Research (AWI), also suggest that the situation has grown critical. AWI's results show that permafrost in the flat shelf is perilously close to thawing. Three to 12 kilometers from the coast, the temperature of sea sediment was -1 to -1.5 degrees Celsius, just below freezing. Permafrost on land, though, was as cold as -12.4 degrees Celsius. "That's a drastic difference and the best proof of a critical thermal status of the submarine permafrost," said Shakhova.

Paul Overduin, a geophysicist at AWI, agreed. "She's right," he said. "Changes are far more likely to occur on the sea shelf than on land."

Climate change could give an additional push to these trends. "If the Arctic Sea ice continues to recede and the shelf becomes ice-free for extended periods, then the water in these flat areas will get much warmer," said Overduin. That could lead to a situation in which the temperature of the sea sediment rises above freezing, which would thaw the permafrost.

"We don't have any data on that -- those are just suspicions," the Canadian scientist said. Natalia Shakhova also passed on the question of whether to expect a gradual gas emission or an abrupt burst of large quantities of methane. "No one can say right now whether that will take years, decades or hundreds of years," she said. But one cannot rule out sudden methane emissions. They could happen at "any time."

One thing is clear, though: The thawing of the Arctic sea floor will create "new potential sources for methane ... which no one had reckoned with until now," said Laurence Smith, a professor for geography at the University of California in Los Angeles. Smith is researching North Pole frost zones and expects that a thawing of the permafrost will "supply fuel for methane engines."

The first methane rocket thruster was tested by the US's National Aeronautics and Space Administration (NASA) in 2007, and methane from manure has been collected as "biogas" to heat and power homes (more...) in experimental German towns.

In any case, the team taking part in the Siberian study installed a number of probes in the Laptev Sea, a central part of the broad Siberian shelf sea. These probes are measuring the temperature on the upper edge of the submarine permafrost. Overduin wants to pull up the probes in August. Then, for the first time, scientists will have access to a full year's worth of data on the conditions of the sea floor.

For her part, Shakhova thinks researchers should be doing a lot more. She says too little is known about the fragile shelf sediment and the methane it stores, which could be explosive for the environment. "Actually," she says, "this is a wake-up call for science."

This is BAD.

[lordofFNORD]

Damn. This sucks.

The 540 billion tons, in CO2 equivalence would be about 10^13 tons. Released over 300 years, thats approximately double greenhouse gas release rates all by itself. Shit.

[Vehrec]

. . . WEll, it's time to start singing the DOOM song people. So Long and thanks for all the fish, I'm going to do my best to preserve flora and fauna on the moon while I wait for the rest of you to stabilize this kooky plant's climate before it reverts to a Cretaceous state. Fortunately, Methane has a 10 year lifespan in the atmosphere, and unless replenished, most of this stuff should break down quickly.

[Guardsman Bass]

This is one of the conditions that Mark Lynas brought up in his book for getting to a 5 Degree Celsius rise. It would be nice, though, if they actually tried to get a figure on the time frame and trigger for this.

[Admiral Valdemar]

I have Six Degrees but haven't got to that chapter. I do recall the article in the Indy last February and the ridiculing it got here as alarmist. Seems five degrees is hopelessly optimistic yet again from the IPCC and others compared to unfolding events.

[UCBooties]

To me, this represents one of the scariest things about Global Warming. The whole process is like an avalanche. By the time the earth has warmed enough to start this stuff going, it won't matter how much we cut emissions.

[PeZook]

Hmm...so, basically, the Earth has an immune system against human civilization, and it just kicked in

[Tolya]

All your methane are belong to us?

[Tolya]

We can kill all cows on the planet to even it out a bit...

It would, however, spawn a massive nuclear conflict with India.

We're fooked.

[Sikon]

During the Paleocene/Eocene thermal maximum (PETM) 55 million years ago, there was major temperature rise accompanied by the release of a large quantity of methane in ocean gas hydrates, rather rapidly in geological terms, over "the relative geological instant of about 100,000 years." Fossilized remains have been found in the arctic of plant life after the event which would only have grown under warm conditions.

But why wasn't it faster? Why didn't the warming from the release of the first few percent cause all the rest to be released within a few years rather than over millennia?

The very surface of the oceans can warm relatively quickly, but the water many meters down is a different matter. To raise the average temperature of earth's oceans by one degree takes 1100 times as much energy as to do so for the atmosphere, due to the vastly greater mass of the oceans compared to the mass of the atmosphere and the specific heat difference.

Of course, the top portion of ocean water can warm much faster than the depths. As implied by the IPCC in the 2001 and 2007 reports, methane trapped near the surface on land and in relatively shallow oceanic waters can be released long before the bulk of it that is deeper down.

Permafrost at shallow depths on land:

Warming, thawing and decrease in area extent of terrain underlain by permafrost are expected in response to climatic change in the 21st century [...]

By the middle of the century, the depth of seasonal thawing may increase on average by 15 to 25%, and by 50% and more in the northernmost locations; and by 2080, it is likely to increase by 30 to 50% and more over all permafrost areas [...]

Wetting, from increased precipitation and permafrost thawing, is projected to increase fluxes of methane relative to carbon dioxide from the active layer and thawing permafrost [...]

Observations indicate substantial increases in CH4 released from northern peatlands that are experiencing permafrost melt (Christensen et al., 2004; Wickland et al., 2006).

... from the IPCC 2007 report here and here.

Methane hydrates underwater:

On the continents, stable gas hydrates can be found only at depths of several hundreds of meters, making it unlikely that they will be released by climate change in the coming centuries. In the northern seas, gas hydrates may be deposited in the near-bottom zone, and their decomposition is likely to occur if deepwater temperature rises by even a few degrees.

There has been some methane release from such observed for a number of years, like the IPCC 2001 report mentioned:

There is evidence of methane hydrate destabilization and release with warming of coastal ocean bottomwater from other parts of the world (Kennett et al., 2000).

As a consequence of the large heat capacity of the oceans, the timeframe for release of the bulk of methane hydrates deeper down is in the range of millennia, as it takes that long for deep seawater to rise in temperature by several degrees rather than only surface water warming that much.

Such is illustrated by this relevant part of the IPCC 2007 report:

Recent modelling suggests that today’s seafloor CH4 inventory would be diminished by 85% with a warming of bottom water temperatures by 3°C (Buffett and Archer, 2004). Based on this inventory, the time-dependent feedback of hydrate destabilisation to global warming has been addressed using different assumptions for the time constant of destabilisation: an anthropogenic release of 2,000 GtC to the atmosphere could cause an additional release of CH4 from gas hydrates of a similar magnitude (~2,000 Gt(CH4)) over a period of 1 to 100 kyr (Archer and Buffett, 2005). Thus, gas hydrate decomposition represents an important positive CH4 feedback to be considered in global warming scenarios on longer time scales.

From here

1 to 100 kyr = 1000 to 100000 years.

As the previous examples illustrate, there is some methane release from both permafrost and underwater sources right now, and there has been for a number of years ... but it takes a long time for the bulk of it to thaw, due to the thermal insulation when most of it is under hundreds of meters of seawater or more.

Methane hydrates have long been one of the focuses of climate research, such as the example of this article from a couple decades ago:

Role of methane clathrates in past and future climates
[...]
Abstract
Methane clathrates are stable at depths greater than about 200 m in permafrost regions and in ocean sediments at water depths greater than about 250 m, provided bottom waters are sufficiently cold. The thickness of the clathrate stability zone depends on surface temperature and geothermal gradient. Average stability zone thickness is about 400 m in cold regions where average surface temperatures are below freezing, 500 m in ocean sediments, and up to 1,500 m in regions of very cold surface temperature (<-15 °C) or in the deep ocean. [...]

The time scale for thermal destabilization is set by the thermal properties of sediments and is on the order of thousands of years. [...]

From here.

Methane is mostly the same as natural gas, though, to be more precise, conventional natural gas is 70% to 90% methane while including a small amount of ethane and other chemical species.

Methane hydrate is stable in ocean floor sediments at water depths greater than 300 meters, and where it occurs, it is known to cement loose sediments in a surface layer several hundred meters thick. [...]

Recent mapping conducted by the USGS off North Carolina and South Carolina shows large accumulations of methane hydrates. [...]

USGS scientists estimate that these areas contain more than 1,300 trillion cubic feet of methane gas, an amount representing more than 70 times the 1989 gas consumption of the United States.

From here.

The biggest reason for hydrate's appeal is the sheer volume of deposits buried beneath marine sediment and permafrost regions of the globe. [...]

As a source for natural gas, hydrate today is about where coal bed methane was 15 years ago, says Michael Max, a hydrate expert formerly with the Naval Research Laboratory in Washington, D.C. "Coal bed methane was a classic, unconventional gas play," with more than a few doubters, Max says. "Now it supplies around eight percent of the U.S natural gas supply. We think hydrate has a similar trajectory."

From here

Methane hydrates are likely to be consumed a lot in the future. There's a tendency towards expanded consumption of natural gas, from electricity to the natural-gas-to-liquids (NGLs) conversion which is increasingly being used as a substitute for fuel from conventional crude oil.

Superficially, that might seem environmentally like a good thing since, if the methane went into the atmosphere unburned, it does have about 20 times the radiative forcing effect of CO2 (averaged over 100 years, taking into account that the bulk of it lasts less long in the atmosphere). Burning it prevents such, converting the methane into CO2 and H2O.

However, since human consumption can occur at far faster timeframes than the limited ordinary release rate from warming alone, the bulk of the methane consumed and burned would be that which would otherwise have stayed harmlessly underwater for millennia. Renewables and nuclear energy can still be environmentally better even from the standpoint of global warming, as well as for avoiding dependence on a resource that is still a limited supply like other fossil fuels.

[Admiral Valdemar]

Additionally, the flat trend since '98 in methane concentration from the NOAA data is often seen as being caused by less gas flaring and better efficiency within the fossil fuel industry such as fixing leaking pipes that can carry methane and other alkanes.

With Japan and the US teaming up to try and take advantage of these vast deposits and given their unstable nature, I don't think the permafrost finally thawing is going to be the main threat here. It only takes one cock-up by a rig accessing such shallow deposits to cause a methane "burp" of significant size. Deeper down in the ocean, it's not so much an issue as any release would be absorbed by the ocean above. But those kinds of fields of hydrates are less economical to process, and so we must assume those of greater threat will be a priority for any energy business.

Fortunately, methane has a far shorter half-life than CO2 or other GHGs, so if a minor accident happened, it wouldn't be stuck adding to the warming process for as long as if it had been a large CO2 release. I fear the only way anyone will take notice of that risk is after it has happened. So even with that small mercy, it's not something I'd want to see take place in my lifetime at least.

[Singular Intellect]

Ironic; here we are facing a major global energy crisis, and now we're face with a serious threat of our atmosphere be contaminated by...get this....too much fuel.

[Alferd Packer]

With Japan and the US teaming up to try and take advantage of these vast deposits and given their unstable nature, I don't think the permafrost finally thawing is going to be the main threat here. It only takes one cock-up by a rig accessing such shallow deposits to cause a methane "burp" of significant size. Deeper down in the ocean, it's not so much an issue as any release would be absorbed by the ocean above. But those kinds of fields of hydrates are less economical to process, and so we must assume those of greater threat will be a priority for any energy business.

Not to be crass (though I am), but wouldn't it really be a methane "fart"? Isn't it methane that contributes to the stench of farts, or is it some other chemical? I have this image in my head of everywhere north of 72 degrees latitude reeking of farts in 2050.

[lordofFNORD]

Isn't it methane that contributes to the stench of farts, or is it some other chemical?

Nope. Although methane is a component of flatulence(for some animals more than others), it is odorless. The parts that smell are primarily amines and sulfides.

Because methane gas is toxic and explosive, a small amount of an odorous gas is often include, to ease the detection of leaks, often similar to the odorous gases in flatulence. That's why this myth is common.

[lordofFNORD]

Ghetto Edit:
Actually, methane is not toxic, only a potential asphyxiant if it displaces oxygen in an enclosed space. My bad. Still explosive, though.