BobInget wrote: And if and when the permafrost goes into an irreversible meltdown, you might want to pack your bags and move to Tierra del Fuego.
BobInget wrote:
The good news about the permafrost is that it's probably not going to start seriously melting until the middle of the century or beyond. The bad news is that it might already be starting:
But Plekhanov and his team believe that it is linked to the abnormally hot Yamal summers of 2012 and 2013, which were warmer than usual by an average of about 5°C. As temperatures rose, the researchers suggest, permafrost thawed and collapsed, releasing methane that had been trapped in the icy ground.
Other researchers argue that long-term global warming might be to blame — and that a slow and steady thaw in the region could have been enough to free a burst of methane and create such a big crater. Over the past 20 years, permafrost at a depth of 20 metres has warmed by about 2°C, driven by rising air temperatures1, notes Hans-Wolfgang Hubberten, a geochemist at the Alfred Wegener Institute in Potsdam, Germany.
Hubberten speculates that a thick layer of ice on top of the soil at the Yamal crater site trapped methane released by thawing permafrost. “Gas pressure increased until it was high enough to push away the overlying layers in a powerful injection, forming the crater,” he says. Hubberten says that he has never before seen a crater similar to the Yamal crater in the Arctic.
Larry Hinzman, a permafrost hydrologist at the University of Alaska in Fairbanks and director of the International Arctic Research Center, says that such craters could become more common in permafrost areas as the region heats up.
Graeme wrote:We started discussing these in the runaway thread. Rockdoc is trying to convince us that they are pingos ... but if you look at images of them from wiki, they don't look like pingos.
dohboi wrote:Good thread, free so far of WUWT ditto-heads.
The other round lakes in the region were mostly formed long ago, some during the "Holocene Optimum" when global temperatures were nearly as warm as they are now. I'm guessing we will see quite a few more of these in the coming weeks and years.
By now, you’ve heard of the crater on the Yamal Peninsula. It’s the one that suddenly appeared, yawning nearly 60 metres in diameter.
There’s now a substantiated theory about what created the crater. And the news isn’t good.
Geochemist Hans-Wolfgang Hubberten of Germany’s Alfred Wegener Institute explained: “Gas pressure increased until it was high enough to push away the overlaying layers in a powerful ejection, forming the crater.”
According to a recent Nature article, “air near the bottom of the crater contained unusually high concentrations of methane - up to 9.6 per cent - in tests conducted at the site on 16 July, says Andrei Plekhanov, an archaeologist at the Scientific Centre of Arctic Studies in Salekhard, Russia. Plekhanov, who led an expedition to the crater, says that air normally contains just 0.000179 per cent methane.”
The scientist said the methane release may be related to Yamal’s unusually hot summers in 2012 and 2013, which were warmer by an average of 5 degrees Celsius.
Scientists contend the thawing of such terrain, rife with centuries of carbon, would release incredible amounts of methane gas and affect global temperatures.
One litre of fully saturated methane clathrate solid contains about 120 grams of methane (or around 169 litres of methane gas at 0°C and 1 atm).
On July 23, Ulf Hedman – who is aboard the Oden and who is Science Coordinator for the Swedish Polar Research Secretariat – gave a vivid description of the discovery in his blog:
We are ‘sniffing’ methane. We see the bubbles on video from the camera mounted on the CTD or the Multicorer. All analysis tells the signs. We are in a [methane] mega flare. We see it in the water column we read it above the surface an we follow it up high into the sky with radars and lasers. We see it mixed in the air and carried away with the winds. Methane in the air. Where does it come from? Is it from the old moors and mosses that used to be on dry land but now has sunken into the sea. Does it come from the deep interior of the Earth following structures in the bedrock up into the sand filled reservoirs collecting oil and gas then leaking out upwards, as bubbles through the sea bed into the water, into the mid-water sonar, the Niskin bottles the analysis and into our results?
Where does the methane come from? Is it organic or not? What’s the volume? How much is carried up into the air? Is there an effect on the climate? One mega flare does not tell the truth. It’s not evidence enough.
We carry on for the next station.
Cid_Yama wrote:I have to admit I never expected to see anything so dramatic as hydrate dissociation. There was already enough free methane gas, dissociated by geothermal flux, to do the job. But this really does look like hydrate dissociation.
The depth of the crater also appears to lend credence to it being due to hydrate dissociation.
The holes are likely a type of sinkhole formed from melting permafrost or ice, which most likely erupted due to a collection of natural gas within the underground spaces
"My personal opinion is it's some type of sinkhole," said Vladimir Romanovsky, a geophysicist who studies permafrost at the University of Alaska Fairbanks. Sinkholes are pits in the ground formed when water fails to drain away.
The water likely came from melting permafrost or ice, said Romanovsky, who has spoken with the Russian scientists investigating the site. But whereas most sinkholes suck collapsed material inside, "this one actually erupted outside," he told Live Science. "It's not even in the [scientific] literature. It's pretty new what we're dealing with," he added.
But Romanovsky said the hole doesn't look like a typical collapsed pingo; such features usually form from larger mounds that slowly cave in over a period of decades, with all the material falling inside.
From the photo of the Yamal crater, "it's obvious that some material was ejected from the hole," Romanovsky said. His Russian colleagues who visited the site told him the dirt was piled more than 3 feet (1 m) high around the hole's edges.
Temperatures across the Arctic are warming roughly twice as fast as the rest of the globe, largely due to the reduction in the amount of sunlight reflecting off of white, snow-covered ground. “At some point, we might get into a state of permafrost that is not comparable to what we know for 100 years or so, some new processes that never happened before,” says geologist Guido Grosse of the Alfred Wegener Institute for Polar and Marine Research in Germany.
The mysterious craters in far northern Russia are just such an example. “There is nothing described in the scientific literature than can really, fully explain those craters,” says Grosse, who is headed to the Lena River Delta in Siberia this summer, which hosts a joint German-Russian research station. The most likely explanation for the newly discovered craters in Russia is an accumulation of methane over centuries or more that then burst out of the thawing ground sometime in the last few years. “High pressure built up and [the ground] literally popped open,” explains biogeochemist Kevin Schaefer of the U.S. National Snow and Ice Data Center. “If it is indeed caused by melting methane ice, we should expect to see more.”
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