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Arctic Methane Alert — Ramp-Up at Numerous Reporting Stations Shows Signature of an Amplifying Feedback

Over the past few months, reporting stations around the Arctic have shown a ramping rate of atmospheric methane accumulation. The curves in the graphs are steepening, hinting at a growing release of methane from a warming Arctic environment.

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Alert, Canada Methane June 1 2015

(Alert, Canada methane graph shows atmospheric methane increases in the range of 20 parts per billion in just one year. This rate of increase is 2-3 times the global average for the past five years. A skyrocketing rate of increase. Image source: NOAA ESRL.)

A Massive Thawing Carbon Store in the Far North

The science is pretty settled. There’s a massive store of ancient carbon now thawing in the Arctic.

In the land-based permafrost alone, this store is in the range of 1.3 billion tons — or nearly double the volume in the atmosphere right now. Arctic Ocean methane hydrates in the East Siberian Arctic Shelf add another 500 billion tons. A rather vulnerable store that does not include hundreds of billions of additional tons of carbon in the deeper methane hydrates around the Arctic in places like the Gakkel Ridge, in the Deep Waters off Svalbard, or in the Nares Strait. Massive carbon stores of high global warming potential gas locked in frozen ground or in ice structure upon or beneath the sea bed.

But now human beings — through fossil fuel emissions — are dumping heat trapping gasses into the atmosphere at an unprecedented rate. These gasses are most efficient at trapping heat in the colder, darker regions of the world. And, due to a combination of massive Northern Hemisphere burning, and release from the Arctic carbon stores themselves, the highest concentrations of greenhouse gasses can be found exactly where they are needed least — in the world’s far northern zones .

Arctic Overburden May 29

(The Arctic consistently shows an overburden of methane gas — both at the ground and upper levels of the atmosphere as seen in this METOP graphic from May 29. Such an overburden is but one of many proxy indicators of a ramping rate of release.)

This accumulation and overburden of heat trapping gasses is causing the Arctic to rapidly warm. A rate of warming (now at half a degree Celsius per decade for most regions) that is providing a heat forcing pushing the ancient carbon stores to release. A heat forcing now greater than at any time in the past 150,000 years (and likely more due to the fact that the Eemian Arctic was rather cool overall). A heat forcing rapidly ramping toward at least a range not seen since major glaciation began in the Northern Hemisphere 2-3 million years ago.

The problem for science, then, is two-fold. First, as oceans warm and permafrost thaws, how rapidly will the carbon stores release? And, second, how much of that carbon store will release as CO2, and how much will release as methane? From the point of view of global warming, both CO2 and Methane emissions feedback is a bad outcome of human-forced warming. But methane, which has a global warming potential of between 25 and 120 times CO2 over human-relevant timescales, has a real potential to make an already bad human heating of the Earth System much, much worse.

Methane Bubbles in Thermokarst Lake

(Image source via Science 2.0.)

Most Arctic Reporting Stations Show Rapid Ramping of Methane Gas Accumulation

For this reason, monitoring methane gas accumulation in the Arctic is a key feature of global climate change risk analysis. If the Arctic shows a spiking rate of methane accumulation, then the carbon stores are more susceptible to rapid release of potent heat trapping gasses and we are facing a high urgency situation in need of rapid global response.

Over the past decade, the Arctic has shown numerous isolated or regional spikes to very high methane levels with an overall continued accumulation within the atmosphere. The Arctic also displayed a major overburden of both methane and CO2 — proxy indications of local carbon store feedbacks already ongoing on a minor-to-moderate scale. This combination of overburden and spikes provided a troubling context, especially when adding in observations of methane store release through thermokarst lakes and, later, blow-holes in locations like Yamal, Russia. But up until last year, we had not seen a third, and more troubling, indicator — the ramping rates of atmospheric methane accumulation that would be an early warning that the Arctic carbon store was indeed starting to blow its stack.

But now, that signal is starting to show up at almost every Arctic reporting station. A steepening curve in the Arctic atmospheric methane graphs. A signal we really, really don’t want to be bearing witness to:

Barrow Methane June 1 2015Alert, Canada Methane June 1 2015

Summit Greenland Methane June 1 2015Svalbard Methane June 1 2015

(Major reporting stations from Svalbard to Barrow show a ramping atmospheric methane accumulation [Click on individual images to expand]. It’s a signal that is yet one more indicator of an amplifying methane and greenhouse gas feedback to human warming now going on in the Arctic. Images provided by NOAA ESRL.)

Now, it seems, at the very least, we are witnessing a spike in Arctic atmospheric methane accumulation. Let’s hope it’s just a spike and not the start of another ugly exponential curve associated with human-forced atmospheric warming. But if we are witnessing the early ramp of such a curve, we should be clear that we are now in the context of a worst-case climate change scenario.

Hot-Button Topic of Critical Importance

For years, conjecture over the possible rate of Arctic Methane release in a human-warmed Arctic has been the source of extreme scientific and media-based controversy. Major oil companies have used the issue as an excuse to continue fossil fuel burning (irresponsibly spreading the meme — ‘we’re screwed, so we may as well just keep burning anyway’). Major climate scientists and related media outlets have sought to tamp down concern over large-scale methane release by issuing articles with titles like ‘Apocalypse Not’ with many generally insisting that there is practically zero likelihood of a large-scale methane release or major amplifying feedback. Meanwhile, the observational studies have continued to indicate risk of at least moderate and possibly strong methane feedback in an age of rapid human heating of the Arctic environment (studies like this recent paper which observed microbes tripling the rate of methane gas release in thermokarst lakes as a response to Arctic temperature increase.) Finally, a group of very concerned observational scientists like Natalia Shakhova, Igor Simeletov and Peter Wadhams have warned that a large-scale methane release is likely imminent and begs a major response from the global community (sadly, many of these proposed responses have come in the form of geo-engineering — methods which are far less likely to succeed and far more likely to generate unforeseen and highly disruptive consequences than simple cessation of human fossil fuel emission and a transition to carbon-negative civilizations).

Mauna Loa Methane June 1 2015

(Mauna Loa methane measure through June 1, 2015 shows that lower Latitude regions are also starting to follow a ramping rate of increase. Image source: NOAA ESRL.)

All this controversy aside, what we observe now is the following:

  1. Arctic methane and CO2 overburden — proxy indication of environmental release.
  2. Increasing rates of release, indications of increasing release, or possibly increasing release from single sources such as thermokarst lakes, peat bogs, wildfires, and sea bed hydrates and submerged tundra.
  3. A multiplication of observed or discovered methane release sources — thermokarst lakes, methane blow holes, wildfires etc.
  4. A ramping rate of atmospheric methane accumulation at reporting stations throughout the Arctic (most but not all stations).
  5. A ramping rate of atmospheric methane accumulation from global proxy monitors like Mauna Loa and in the global atmospheric average.

Together, these observations represent a troubling trend that, should it continue, will be proceeding along or near a worst-case climate sensitivity track. As such, these new ramping rates of increase in Arctic atmospheric monitors are a very unfortunate indicator.

Links:

NOAA ESRL

NOAA OSPO

Arctic Methane Skyrocketing

Microbes in Thermokarst Lakes Increase Methane Generation with Warming

Arctic Sea Ice Melt, Methane Release Shows Amplifying Feedback to Human-Caused Climate Change

 

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Mauna Loa Methane Measure Shows Rising Rates of Increase Through End 2014

Mauna Loa Methane early December

(Atmospheric methane levels as measured at the Mauna Loa Observatory. Image source: NOAA/ESRL.)

Atmospheric methane levels as measured by the Mauna Loa Observatory (MLO) showed a continued steepening rate of increase through late 2014 — featuring one rather troubling spike late last month.

The measure, which has been recording atmospheric methane levels since the middle of the 20th Century, continued to ramp higher with readings hitting an average of 1850 parts per billion by late November.

Notably, this increase is at a faster pace than yearly averages for all of the last decade.

In addition, a single spike to 1910 parts per billion took place last month. This large departure of 60 parts per billion above the average was somewhat unusual for the Mauna Loa measure. The collection site is rather far from human or Arctic emissions sources which makes it less likely to feature anomalous spikes due to local influences. This particular spike also represents the largest single departure from the base line measure since 1984 (when the ESRL record begins).

Overall drivers of the more recent increase in global methane levels beginning around 2007 come from an increase in human emissions (likely due to rising rates of fossil fuel exploitation — primarily through hydrofracking and coal mining) as well as what appears to also be an increase in Arctic emissions. Large methane sources in Siberia, over the East Siberian Arctic Shelf, in the Laptev Sea, the Nares Strait, and west of Svalbard have been observed in both satellite monitors and through observations taken by scientists and researchers on the ground. Overall, a significant overburden of greenhouse gasses centers on the Arctic and appears to be enhanced by local carbon (methane and CO2) sources in the region.

More comprehensive measurements of methane releases over Alaska (according to NASA JPL), on the other hand, have not yet shown methane release departures above the global norm for land areas. But the observational record for Alaska composes just one year (2012), so there is no way to yet determine if permafrost carbon and methane releases from the tundra in that region increased to achieve their current rates. It is worth noting generally that the terrestrial zone for Alaska and its off shore region are not, as yet, major carbon release hot spots.

Global Warming Potential at Least 20 Times CO2

Methane (CH4) is an important greenhouse gas due to the fact that its global warming potential (GWP) over short periods is much higher when compared to a similar volume of CO2 (most measures consider the GWP of methane to be 20 times that of a similar volume of CO2). That said, methane’s residence time in the atmosphere is much shorter than CO2 and CO2 volumes are much larger. So CO2 is considered to be a more important gas when it comes to long term climate change. Nonetheless, CH4 increases since the start of the industrial revolution put it as the #2 gas now forcing the world to warm.

Very large outbursts of CH4 from the global carbon store (including terrestrial and ocean stores) during the Permian and PETM are hypothesized to have set off very rapid increases in global temperature. For some prominent researchers, this potential hazard is seen to be very low under current warming conditions. Others, however, seem very concerned that a rapid methane outburst under the very fast rate of human warming could be a tipping point we are fast approaching.

Observations in a Murky Scientific Context

It is important to note that the current profile of atmospheric methane increase does not yet look like one of catastrophic release. Instead, what we see is an overall ramping up of atmospheric levels.

The issue of catastrophic release potential — raised by Peter Wadhams, the Arctic Methane Emergency Group, and Dr. Simeletov and Shakhova among others — is not one that is certain or settled in the science.

As an example, Dr. Shakhova identifies a substantial but non-catastrophic 17 megaton atmospheric release from the East Siberian Arctic Shelf (equal to about 8 percent of the human emission and a substantial increase from a previous estimate of 8 megatons per year in 2010) as currently ongoing. However, both Simeletov and Shakhova have been the object of criticism due to their identification of a risk of a 3.5 gigaton per year methane release should all the East Siberian Arctic Shelf methane hot spots become active. Such a release would, in one year, nearly double the amount of all methane currently in the atmosphere (5 gigatons).

Dr. Peter Wadhams, another Arctic expert, has also received criticism for his assessment that a 50 gigaton release from the large subsea Arctic methane stores could be possible as sea ice retreat spurs Arctic Ocean sea floors to warm.

Other scientists such as GISS lead Gavin Schmidt and prominent Earth Systems modeler David Archer have noted that such very large releases aren’t currently likely. They point to natural traps that tend to tamp down sea based release rates (sometimes stopping as much as 90 percent of a destabilized methane source from hitting the atmosphere). They also note that current warming has probably not yet exceeded levels seen during the Eemian (130,000 years ago) and no large methane releases were observed at that time from Arctic carbon stores like the ESAS. They tend to take the view that any increasing rate of release coming from Arctic methane stores in particular and Arctic carbon stores in general will be very slow — so slow as to not be a significant amplifier of human warming (less than 5 percent) this century.

In general, between these two rather extreme and increasingly polarized views on Arctic methane, there appears to be very little in the way of middle ground. Although, a loosely related survey of permafrost carbon experts found a consensus opinion that the total carbon emission (including CO2 and methane) from land based tundra alone would equal between 10 and 35 percent of the current annual human emission by the end of this Century. It’s worth noting that this survey assessment does not include potential releases from the submerged permafrost in the ESAS or releases from other global carbon stores as a result of human warming.

The current rapid pace of human-caused warming — heating some regions of the Arctic as fast as 0.5 to 1 C per decade — also caused some of Archer and Schmidt’s scientific forebears, particularly James Hansen, to be rather less dismissive of the potential for a significant release from global methane stores, especially those in the Arctic. In any case, current human greenhouse gas emissions of nearly 50 gigatons CO2e each year are now in the process of pushing global temperatures past Eemian thresholds. An excession likely to elevate Anthropocene temperatures beyond all Eemian estimates before the mid 2030s under current rates of global greenhouse gas emissions and expected increases in fossil fuel burning.

So it is in this murky scientific context that we must interpret risks involving a continuing and apparently ramping rate of atmospheric methane increase. And what we can say with certainty is that there is little evidence that we are now hitting an exponential rise in global atmospheric methane levels. But that there is some evidence that a risk for such an event is real and requires much more detailed research and public dissemination of information to put what are some very valid concerns to rest.

Links:

NOAA ESRL

Alaska Methane Survey by JPL

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