Positive feedbacks

19 ways climate change is now feeding itself

Guy McPherson

“This visualization shows the extent of Arctic sea ice on Aug. 26, 2012, the day the sea ice dipped to its smallest extent ever recorded in more than three decades of satellite measurements, according to scientists from NASA and the National Snow and Ice Data Center.” Read More. Photo: NASA Goddard Photo and Video/Flickr.

Transition Voice,

19 August, 2013

This essay updates my earlier effort to tally and describe self-reinforcing feedback loops with respect to climate change. At that time, seven months ago, we had strong evidence of nine such catastrophic phenomena. The nineteen I currently know about are described below. Only the final one is reversible over a temporal span relevant to humanity.

1. Methane hydrates are bubbling out the Arctic Ocean (Science, March 2010). According to NASA’s CARVE project, these plumes were up to 150 kilometers across as of mid-July 2013. Whereas Malcolm Light’s 9 February 2012 forecast of extinction of all life on Earth by the middle of this century appears premature because his conclusion of exponential methane release during summer 2011 was based on data subsequently revised and smoothed by U.S. government agencies, subsequent information — most notably from NASA’s CARVE project — indicates the grave potential for catastrophic release of methane. 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.
   
   
2. Warm Atlantic water is defrosting the Arctic as it shoots through the Fram Strait (Science, January 2011).
   
   
3. Siberian methane vents have increased in size from less than a meter across in the summer of 2010 to about a kilometer across in 2011 (Tellus, February 2011).
   
   
4. Drought in the Amazon triggered the release of more carbon than the United States in 2010 (Science, February 2011).
   
   
5. Peat in the world’s boreal forests is decomposing at an astonishing rate (Nature Communications, November 2011).
   
   
6. Invasion of tall shrubs warms the soil, hence destabilizes the permafrost (Environmental Research Letters, March 2012).
   
   
7. Greenland ice is darkening (The Cryosphere, June 2012).
   
   
8. Methane is being released from the Antarctic, too (Nature, August 2012). According to a paper in the 24 July 2013 issue of Scientific Reports, melt rate in the Antarctic has caught up to the Arctic.
   
   
9. Russian forest and bog fires are growing (NASA, August 2012), a phenomenon consequently apparent throughout the northern hemisphere (Nature Communications, July 2013). The New York Times reports hotter, drier conditions leading to huge fires in western North America as the “new normal” in their 1 July 2013 issue. A paper in the 22 July 2013 issue of the Proceedings of the National Academy of Sciences indicates boreal forests are burning at a rate exceeding that of the last 10,000 years.
   
   
10. Cracking of glaciers accelerates in the presence of increased carbon dioxide (Journal of Physics D: Applied Physics, October 2012).
    
    
11. The Beaufort Gyre apparently has reversed course (U.S. National Snow and Ice Data Center, October 2012).
    
    
12. Exposure to sunlight increases bacterial conversion of exposed soil carbon, thus accelerating thawing of the permafrost (Proceedings of the National Academy of Sciences, February 2013).
    
    
13. The microbes have joined the party, too, according to a paper in the 23 February 2013 issue of New Scientist.
    
    
14. Summer ice melt in Antarctica is at its highest level in a thousand years: Summer ice in the Antarctic is melting 10 times quicker than it was 600 years ago, with the most rapid melt occurring in the last 50 years (Nature Geoscience, April 2013).
    
    
15. Floods in Canada are sending pulses of silty water out through the Mackenzie Delta and into the Beaufort Sea, thus painting brown a wide section of the Arctic Ocean near the Mackenzie Delta brown (NASA, June 2013).
    
    
16. Surface meltwater draining through cracks in an ice sheet can warm the sheet from the inside, softening the ice and letting it flow faster, according to a study accepted for publication in the Journal of Geophysical Research: Earth Surface (July 2013). It appears a Heinrich Event has been triggered in Greenland. Consider the description of such an event as provided by Robert Scribbler on 8 August 2013:
    
    

    In a Heinrich Event, the melt forces eventually reach a tipping point. The warmer water has greatly softened the ice sheet. Floods of water flow out beneath the ice. Ice ponds grow into great lakes that may spill out both over top of the ice and underneath it. Large ice damns (sic) may or may not start to form. All through this time ice motion and melt is accelerating. Finally, a major tipping point is reached and in a single large event or ongoing series of such events, a massive surge of water and ice flush outward as the ice sheet enters an entirely chaotic state. Tsunamis of melt water rush out bearing their vast floatillas (sic) of ice burgs (sic), greatly contributing to sea level rise. And that’s when the weather really starts to get nasty. In the case of Greenland, the firing line for such events is the entire North Atlantic and, ultimately the Northern Hemisphere.

    
    
17. Breakdown of the thermohaline conveyor belt is happening in the Antarctic as well as the Arctic, thus leading to melting of Antarctic permafrost (Scientific Reports, July 2013).
    
    
18. Loss of Arctic sea ice is reducing the temperature gradient between the poles and the equator, thus causing the jet stream to slow and meander. One result is the creation of weather blocks such as the recent very high temperatures in Alaska. As a result, boreal peat dries and catches fire like a coal seam. The resulting soot enters the atmosphere to fall again, coating the ice surface elsewhere, thus reducing albedo and hastening the melting of ice. Each of these individual phenomena has been reported, albeit rarely, but to my knowledge the dots have not been connected beyond this space. The inability or unwillingness of the media to connect two dots is not surprising, and has been routinely reported (recently including here with respect to climate change and wildfires) (July 2013).
    
    
19. Arctic ice is growing darker, hence less reflective (Nature Climate Change, August 2013).
    
    

Meanwhile, Arctic drilling was fast-tracked by the Obama administration during the summer of 2012.