Thursday, December 29, 2011

Arctic Methane, Emergencies, and Alarmism

Arctic methane has attracted increasing attention over the last several weeks based on new findings presented by a Russian research team from the University of Alaska Fairbanks. The principal members of this team, Natalia Shakhova and Igor Semiletov, published a paper in the journal Science last year in which they reported previously unobserved methane venting over the East Siberian Arctic Shelf (ESAS). These methane plumes were traced to so-called methane hydrates (or "clathrates") found on the seabed. The researchers estimated that 8 tons of methane per year were being released from these sedimentary structures. These findings were particularly troubling given that methane is a much more potent GHG than carbon dioxide (72 times as powerful over a 20-year period).

At this year's fall meeting of the American Geophysical Union (AGU) in San Francisco, Shakhova and Semiletov released new observations from a 2011 expedition to the ESAS. According to Semiletov, "Earlier we found torch-like structures ... but they were only tens of meters in diameter. This is the first time that we've found continuous, powerful and impressive seeping structures, more than 1,000 meters in diameter. It's amazing." These new data have not yet been widely released, but are scheduled for publication next spring.

In response to these developments, some members of the geoengineering community have formed an Arctic Methane Emergency Group. Members of this group tie together observations on methane venting, permafrost thaw scenarios, models of sea-ice retreat, and positive feedback hypotheses to paint a picture of an Arctic on the verge of imminent meltdown:

It is now clear that there are two critical problems confounding one another: the rapid loss of sea ice and the emergence of methane from a thawing seabed. They both call for rapid intervention: to cool the region and to capture the methane. ... There is clearly no longer any alternative to large-scale intervention (also known as "geoengineering") for reducing the risk of disaster. And this has to be done extremely quickly - possible large-scale deployment in Spring 2013 - which is an enormous challenge for the development of new technology and its deployment (see booklet here).

In short, the Group believes that super-GHG methane plumes herald the start of runaway global warming, and only an immediate Arctic geoengineering response can avert catastrophe. Group members call for some combination of SAI, marine cloud brightening, and cloud removal to be deployed a little over a year from now, a proposal which has begun to attract attention in the popular science press.

While declaring a methane emergency and calling for immediate action is rooted in good intentions, such advocacy is both premature and misguided. In scientific terms, the available evidence simply does not support assertions that a worst-case scenario is unfolding. Shakhova and Semiletov have discovered an important phenomenon in the ESAS, but there are no data to indicate that this is a new phenomenon, or that methane venting is increasing at a statistically significant rate, or that venting is tightly connected to sea-ice retreat and the ice-albedo feedback. Arctic climate expert Ed Dlugokencky has written that "There is no evidence from our atmospheric measurements that there has been a significant increase in emissions during the past 20 years from natural methane sources in the Arctic so far." Ice expert Richard Alley states "the physical understanding agrees with the paleoclimatic data that methane can be an important feedback but isn't likely to have giant rapid climate-changing belches." Even Shakhova and Semiletov urge restraint: "we have never stated that the reason for the currently observed methane emissions were due to recent climate change. ... We would urge people ... not jump to conclusions and be open to the idea that new observations may significantly change what we understand about our world."

Demands for quick deployment are also politically unwise. Given the mainstream scientific views described above, such calls will not be heeded, but instead will be attributed to "the scientific fringe," which could in turn contribute to the marginalization of the broader geoengineering community. This would be especially tragic if compelling evidence subsequently emerges that we are indeed at an Arctic tipping point: climate remediation solutions may be dismissed as the science-fiction fantasies of doomsday prognosticators, even if the underlying engineering is sound and deployment warranted by an objective reading of events. Monitoring of Arctic methane venting should be increased, and research on global and regional geoengineering schemes should be intensified, but assertions that we are on the brink of calamity and must act now should cease. There is a difference between vigilance and alarmism, and the Arctic Methane Emergency Group is rapidly drifting toward the latter.

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