As Permafrost Melts, Bacteria Generate Heat, Making Refreezing Potentially Impossible

[hatrack]

Oops!!

Scientists might have to change their projected timelines for when Greenland’s permafrost will completely melt due to man-made climate change, now that new research from Denmark has shown it could be thawing faster than expected. Published Monday in the journal Nature Climate Change, the research shows that tiny microbes trapped in Greenland’s permafrost are becoming active as the climate warms and the permafrost begins to thaw. As those microbes become active, they are feeding on previously-frozen organic matter, producing heat, and threatening to thaw the permafrost even further. In other words, according to the research, permafrost thaw could be accelerating permafrost thaw to a “potentially critical” level.

“The accompanying heat production from microbial metabolism of organic material has been recognized as a potential positive-feedback mechanism that would enhance permafrost thawing and the release of carbon,” the study, conducted by researchers at the University of Copenhagen’s Center for Permafrost, said. “This internal heat production is poorly understood, however, and the strength of this effect remains unclear.”

The big worry climate scientists have about thawing permafrost is that the frozen soil is chock-full of carbon. That carbon is supposed to be strongly trapped inside the soil, precisely because it’s supposed to be permanently frozen — hence, “permafrost.” However, as temperatures in the Arctic have risen due to human-caused climate change, permafrost is thawing, and therefore releasing some of that trapped carbon into the atmosphere. It’s yet another feedback loop manifesting itself in Arctic permafrost regions — as climate change causes it to thaw, the thawing causes more climate change, which causes more thawing, et cetera, et cetera.

What makes this new research so important is that it adds to the urgency of stemming permafrost thaw. Because even without this new discovery of heat-producing microbes, estimates for carbon releases from thawing permafrost have been alarmingly large. According to the National Snow & Ice Data Center, there are about 1,700 gigatons of carbon currently frozen in permafrost — more than the total amount in the atmosphere now (Earth’s atmosphere contains about 850 gigatons of carbon, according to the Center).

EDIT

http://thinkprogress.org/climate/2015/04/08/3643953/greenland-permafrost-thaw-microbes/?utm_source=newsletter&utm_medium=email&utm_campaign=cptop3

[Binkie The Clown]

1. My compost heap gets pretty hot.

So it sounds perfectly logical that decomposing permafrost could do the same. The possibility never occurred to me, although it's pretty obvious in retrospect.

[mackdaddy]

2. I have seen a wet hay bale steaming, and too hot to hold your hand on

Bacterial decay is what causes spontaneous combustion that burns down hay barns.

I think that you have a point that much of these formerly permafrost frozen bogs are like ancient compost come to life now they are out of their deep freeze.

[hatrack]

3. You have to air-channel freshly baled hay if you're stacking it in a barn

Otherwise, big problems.

[NickB79]

4. We'd always salt our hay in the barn

We'd stack a layer of hay in the haybarn, and then walk over it with a 5-gal. bucket of salt and throw handfuls around. Another layer, more salt, etc. The salt supposedly inhibited microbial growth, thereby preventing overheating. It wasn't unheard of for farmers to have barns burned down because of hay being stored too wet: http://ext.wsu.edu/hay-combustion.html

The process of spontaneous combustion involves both microbial growth and chemical changes and may be slow to develop. The wet hay will first stimulate microbial growth and as these organisms grow they produce heat while drying out the surrounding surfaces of the hay for energy. More drying surfaces produces more microbial growth and different types of microbes live and die as the internal bale temperature climbs.

When the bale temperature reaches about 150 Fº the hay is on a one-way street and going the wrong direction! The larger the haystack and the more densely packed the hay is the longer it may take to show signs of internal bale burning. Internal bale temperature may take several weeks before reaching 150 Fº, but from this point on more heat resistant bacteria, called exothermic bacteria, start a process of chemical change that rapidly increases temperatures to the point of spontaneous combustion.

My brother, sister and I always fought over who's turn it was to be the salter, because it was a hell of a lot easier than stacking hundreds of 50-lb bales on a 90F July day.