"Could, may, might"... warnings about the Arctic

 Slight Arctic Warming Could Trigger Abrupt Permafrost Collapse – Study

Moscow News,

20 October, 2020

A few degrees of warming in the Arctic could trigger an abrupt thaw of the permafrost that makes up two-thirds of Russia’s landmass and a subsequent climate change feedback loop, according to a new study based on ancient warming episodes.

Three of the region’s largest warming events in the past 27,000 years coincided with rapidly thawing and collapsing permafrost, said the study published Friday in the Science Advances journal. Its findings are based on an analysis of 8-meter sediment cores retrieved from the bottom of the Arctic Ocean off of Eastern Siberia by a team of Russian, Swedish and U.S. scientists in 2014. 

“This demonstrates that Arctic warming by only a few degrees may suffice to abruptly activate large-scale permafrost thawing,” the study's authors wrote. 

The warming works like “a sensitive trigger for a threshold-like permafrost climate change feedback,” they added. 

Scientists have long argued that climate change could trigger a feedback loop in which melting permafrost releases greenhouse gases like carbon and methane into the atmosphere, further accelerating global warming and permafrost melt.

“Our study indeed suggests that abrupt permafrost thawing represents a tipping point in the climate system,” lead author Jannik Martens told the Inside Climate News website.

When that tipping point will arrive is still an open question, he added.

An Intergovernmental Panel on Climate Change (IPCC) report last year said Russia’s permafrost is expected to thaw at an accelerating rate between now and 2100.  

The IPCC report predicts that 70% of surface-level permafrost could thaw by 2100 if greenhouse gas emissions continue to rise, shifting the world’s “permafrost border” increasingly northward. 

More than 65% of Russia’s territory is located in the planet’s frozen cryosphere. The country is the world’s fourth-largest emitter of greenhouse gases.

The latest study’s co-author Örjan Gustafsson stressed that greenhouse gas emissions from both thawing permafrost and man-made sources will inevitably lead to “dangerous thresholds.”

“The only way to limit permafrost-related greenhouse gas releases is to mitigate climate warming by lowering anthropogenic greenhouse gas emissions,” he told Scientific American. 

https://www.newscientist.com/article/2258169-arctic-sea-ice-loss-could-trigger-huge-levels-of-extra-global-warming/?fbclid=IwAR3VbjMy4RvyXSExf40xZ9PWaAFlnruuwyzOMoc9z7uD3tVqBd0CvD2bHvA

Here is something that is actual

MORE METHANE THREATENS TO REACH THE STRATOSPHERE

Sam Carana, via Facebook

Over the past few years, mean methane levels have risen most strongly at around 300 mb, which is the edge of the stratosphere over the North Pole.

Seafloor methane releases could be triggered by strong winds causing an influx of warm, salty water into the Arctic ocean, as described in an earlier post.

Since little hydroxyl is present in the atmosphere over the Arctic, it is much harder for this methane to get broken down. Even relatively small methane releases could cause tremendous heating, if they reach the stratosphere. Methane rises from the Arctic Ocean concentrated in plumes, pushing away the aerosols and gases that slow down the rise of methane elsewhere, which enables methane erupting from the Arctic Ocean to rise straight up fast and reach the stratosphere.

The IPCC (AR5) gave methane a lifetime of 12.4 years. The IPCC (TAR) gave stratospheric methane a lifetime of 120 years, adding that less than 7% of methane did reach the stratosphere at the time.

The MetOp-1 satellite recorded mean methane levels of 1925 ppb at 293 mb on December 2, 2020 am, with high methane levels present over the Arctic Ocean.

A peak methane level of 2715 ppb was recorded by the SNPP satellite on November 30, 2020 pm at 399.1 mb.

The animation shows high methane levels recorded by the MetOp-2 satellite on December 2, 2020 pm, at a number of altitudes:

- At 1000 mb (close to ground/sea level) a peak methane level of 2129 ppb shows up north of Svalbard.

- At 918 mb, methane peaks at 2408 ppb and high methane levels show up over the Artic Ocean.

- At 815 mb, methane reaches a peak of 2582 ppb and high methane levels are visible over larger parts of the Arctic Ocean.

- At 742 mb, methane reaches a peak of 2663 ppb and high methane levels are visible over even larger parts of the Arctic Ocean.

- At 586 mb, methane reaches a peak of 2518 ppb and high methane levels are visible over a huge part of the Arctic Ocean, while hardly any high levels of methane are visible over land.

- At 293 mb, methane reaches a peak of 2411 ppb and high levels of methane are still visible over the Arctic Ocean, even at this high altitude.