Feedback Loops – A Death Spiral?

By Guy McPherson

An excellent, barely referenced paper by Tim Garrett was written seven years ago and published in the journal Climatic Change. In the article, Garrett pointed out that industrial civilization is a heat engine, and that only complete collapse of industrial civilization would avoid a runaway greenhouse effect. The paper remains largely ignored by the scientific community, having been cited fewer than thirty times since its publication.

Since online publication of Garrett’s paper in 2009, the scientific community has described the passing of more than three dozen self-reinforcing feedback loops. These so-called “positive feedbacks” are analogous to rocks thrown over a cliff: As the rock descends, it picks up speed. As it goes faster, it becomes increasingly difficult to stop. The rock is running away, and so is climate change.

This essay describes one of the many self-reinforcing feedback loops we have triggered. It goes on to list a few others.

Firing the clathrate gun

Methane clathrates are methane molecules (technically, CH4) held within a chemical cage. As the cage warms, the methane is released. Methane has begun bubbling out of the subsea Arctic Ocean, a phenomenon referred to as the “clathrate” gun. Abundant evidence indicates that the clathrate gun has been fired.

About 250 plumes of methane hydrates are escaping from the shallow Arctic seabed, likely as a result of a regional 1oC rise in temperature, as reported in the 6 August 2009 issue of Geophysical Research Letters. Methane bubbling out the Arctic Ocean is further elucidated in Science in March 2010. As described in a subsequent paper in the June 2010 issue of Geophysical Research Letters, a minor increase in temperature would cause the release of upwards of 16,000 metric tons of methane each year. Storms accelerate the release, according to research published in the 24 November 2013 issue of Nature GeoscienceThe latter paper also concludes the East Siberian Arctic Shelf is venting at least 17 teragrams of the methane into the atmosphere each year, up from 0.5 teragrams just 7 years earlier (a teragram is equal to 1 million tons). According to NASA’s CARVE project, these plumes were up to 150 kilometers across as of mid-July 2013. Catastrophically rapid release of methane in the Arctic is further supported by Nafeez Ahmed’s thorough analysis in the 5 August 2013 issue of The Guardian as well as Natalia Shakhova’s 29 July 2013 interview with Nick Breeze. In early November 2013, Shakhova and colleagues published a paper in Nature Geoscience suggesting “significant quantities of methane are escaping the East Siberian Shelf” and indicating that a 50-billion-tonne “burst” of methane could warm Earth by 1.3oC. Such a burst of methane is “highly possible at any time.”

By 15 December 2013, methane bubbling up from the seafloor of the Arctic Ocean had sufficient force to prevent sea ice from forming in the area. Malcolm Light concluded on 22 December 2013, “we have passed the methane hydrate tipping point and are now accelerating into extinction as the … ‘Clathrate Gun’ has begun firing volleys of methane into the Arctic atmosphere.” Two weeks later, in an essay stressing near-term human extinction, Light concluded: “The Gulf Stream transport rate started the methane hydrate (clathrate) gun firing in the Arctic in 2007 when its energy/year exceeded 10 million times the amount of energy/year necessary to dissociate subsea Arctic methane hydrates.” The refereed journal literature, typically playing catch-up with reality, includes an article in the 3 February 2014 issue of Journal of Geophysical Research: Earth Surface claiming, “Sustained submergence into the future should increase gas venting rate roughly exponentially as sediments continue to warm.” Not surprisingly, the clathrate gun began firing in 2007, the same year the extent of Arctic sea ice reached a tipping point. Further confirmation the clathrate gun had been fired came from Stockholm University’s Örjan Gustafsson, who reported from the Laptev Sea on 23 July 2014: “results of preliminary analyses of seawater samples pointed towards levels of dissolved methane 10-50 times higher than background levels.” Jason Box responds to the news in the conservative fashion I’ve come to expect from academic scientists on 27 July 2014: “What’s the take home message, if you ask me? Because elevated atmospheric carbon from fossil fuel burning is the trigger mechanism poking the climate dragon. The trajectory we’re on is to awaken a runaway climate heating that will ravage global agricultural systems leading to mass famine, conflict. Sea level rise will be a small problem by comparison.” Later, during an interview with Vice published 1 August 2014, Box loosened up a bit, saying, “Even if a small fraction of the Arctic carbon were released to the atmosphere, we’re fucked.” It seems we’re there.

Simultaneous with the Laptev Sea mission, several large holes in the ground were discovered in Siberia. The reaction from an article published in the 31 July 2014 issue of Nature indicates atmospheric methane levels more than 50,000 times the usual. An article in the 4 August 2014 edition of Ecowatch ponders the holes: “If you have ever wondered whether you might see the end of the world as we know it in your lifetime, you probably should not read this story, nor study the graphs, nor look at the pictures of methane blowholes aka dragon burps.”

The importance of methane cannot be overstated. Increasingly, evidence points to a methane burst underlying the Great Dying associated with the end-Permian extinction event, as pointed out in the 31 March 2014 issue of Proceedings of the National Academy of Sciences.

Beyond clathrates

Several additional self-reinforcing feedback loops have engaged. I list and describe a few below. A relatively comprehensive list is maintained and updated at Nature Bats Last.

  • Warm Atlantic water is defrosting the Arctic as it shoots through the Fram Strait (Science, January 2011). The extent of Arctic sea ice passed a tipping point in 2007, according to research published in the February 2013 issue of The Cryosphere. On 6 October 2012, Truth-out cites Peter Wadhams, professor of ocean physics at Cambridge University: “The Arctic may be ice-free in summer as soon as 2015. Such a massive loss would have a warming effect roughly equivalent to all human activity to date. In other words, a summer ice-free Arctic could double the rate of warming of the planet as a whole.” Subsequent melting of Arctic ice is reducing albedo, hence enhancing absorption of solar energy. “Averaged globally, this albedo change is equivalent to 25% of the direct forcing from CO2 during the past 30 years,” according to research published in the 17 February 2014 issue of the Proceedings of the National Academy of Sciences. Destabilization of the deep circulation in the Atlantic Ocean may be “spasmodic and abrupt rather than a more gradual increase” as earlier expected, according to a paper published in the 21 February 2014 issues of Science.
  • Siberian methane vents have increased in size from less than a metre across in the summer of 2010 to about a kilometer across in 2011 (Tellus, February 2011). According to a paper in the 12 April 2013 issue of Science, a major methane release is almost inevitable, which makes me wonder where the authors have been hiding. Almost inevitable, they report, regarding an ongoing event, trees are tipping over and dying as permafrost thaws, thus illustrating how self-reinforcing feedback loops feed each other.
  • Drought-induced mortality of trees contributes to increased decomposition of carbon dioxide into the atmosphere and decreased sequestration of atmospheric carbon dioxide. Such mortality has been documented throughout the world since at least November 2000 in Nature, with recent summaries in the February 2013 issue of Nature for the tropics and in the August 2013 issue of Frontiers in Plant Science for temperate North America.

One extremely important example of this phenomenon is occurring in the Amazon, where drought in 2010 led to the release of more carbon than the United States that year (Science, February 2011). The calculation badly underestimates the carbon release. In addition, ongoing deforestation in the region is driving declines in precipitation at a rate much faster than long thought, as reported in the 19 July 2013 issue of Geophysical Research LettersAn overview of the phenomenon, focused on the Amazon, was provided by Climate News Network on 5 March 2014.

Tropical rain forests, long believed to represent the primary driver of atmospheric carbon dioxide, are on the verge of giving up that role. According to a 21 May 2014 paper published in Nature, “the higher turnover rates of carbon pools in semi-arid biomes are an increasingly important driver of global carbon cycle inter-annual variability,” indicating the emerging role of drylands in controlling environmental conditions.

As nearly as I can distinguish, these feedback loops are irreversible at a temporal scale relevant to our species. Once you pull the tab on the can of beer, there’s no keeping the carbon dioxide from bubbling up and out. These feedbacks are not additive, they are multiplicative: they not only reinforce within a feedback, the feedbacks also reinforce among themselves (as realized even by Business Insider on 3 October 2013).

And then what?

As American ecologist Garrett Hardin pointed out long before his death a decade ago, that’s the ecologically relevant question. Anybody interested in individual or societal action must be willing to answer this question.

With respect to ongoing, accelerating climate change, any response to Hardin’s question must include the matter of scale. Individuals are able to abandon a fossil fuel-fueled lifestyle with minor costs, including the disparagement that comes from living outside the mainstream. But, as illustrated by Jevons’ paradox and the Khazzoom-Brookes postulate, individual choices do not translate to societal choices. An individual change in consciousness rarely leads to societal enlightenment. Jumping off the cruise ship of empire will not prevent the ship from striking the iceberg, and it nonetheless results in near-term death of the individual.

The following questions then arise: What shall I do? How shall I live my life?

With respect to dire information about climate change, I’ve come to view my own life as absurd – ditto for industrial civilization. The words of Camus come to mind: “The only way to deal with an unfree world is to become so absolutely free that your very existence is an act of rebellion.” My goal, at this late juncture in my life, is to follow Camus’ lead in treating my every act as one of rebellion.

I hate civilization, yet I’m entrenched in it. I particularly hate industrial civilization, yet shortly after it collapses there will be no habitat where I live. I hate patriarchy, and I’m a white male at the apex of patriarchy. The odds against any one of us being here on this most wondrous of planets are astronomical. And yet here we are. Here I am. The absurdity is profound.



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