Posts Tagged ‘Science Daily’

Compost: a weapon of mass destruction?

December 2, 2010

In another example of how climate change is going to ask us to redefine much of our natural environment – two new studies highlight a growing threat to life as we know it – THE COMPOST BOMB. From Science Daily:

The compost bomb instability is a runaway feedback that occurs when the heat is generated by microbes more quickly than it can escape to the atmosphere. This in turn requires that the active decomposing soil layer is thermally-insulated from the atmosphere.
Catherine Luke explains: “The compost bomb instability is most likely to occur in drying organic soils covered by an insulating lichen or moss layer.”

Similar to the fears of sudden release of methane hydrates from the Arctic Ocean bottom – such a runaway feedback from peatlands will lead to rapid release of carbon, providing yet another (unaccounted for) positive feedback.

The scientists are now working on accounting for this “compost bomb” risk.

The Exeter team is now modelling the potential impact of the compost bomb instability on future climate change, including the potential link to the Russian peatland fires. It is also working to identify other rate-dependent tipping points.

Pee On Ice

November 8, 2010

New research seems to finally be acknowledging the obvious: that water runoff from initial glacier melt is triggering much more dramatic, accelerated melting. Science Daily reports:

melt water in Greenland

“We are finding that once such water flow is initiated through a new section of ice sheet, it can warm rather significantly and quickly, sometimes in just 10 years, ” said lead author Thomas Phillips, a research scientist with Cooperative Institute for Research in Environmental Sciences. CIRES is a joint institute between CU-Boulder and the National Oceanic and Atmospheric Administration.

Contrary to the right-wing-noise-machine’s protestations, the climate science has been, again, overly conservative:

Conventional thermal models of ice sheets do not factor in the presence of water within the ice sheet as a warming agent, but instead use models that primarily consider ice-sheet heating by warmer air on the ice sheet surface. In water’s absence, ice warms slowly in response to the increased surface temperatures from climate change, often requiring centuries to millennia to happen.

Ironically even the scientists must put some softening caveat into the news, saying:

“However, this process is not the ‘death knell’ for the ice sheet. Even under such conditions, it would still take thousands of years for the Greenland ice sheet to disappear…”

That may be so, but even if the ice doesn’t disappear, our coastal cities will be under 20 feet of sea water.

A bit more from this important article:

To quantify the influence of melt water, the scientists modeled what would happen to the ice sheet temperature if water flowed through it for eight weeks every summer — about the length of the active melt season. The result was a significantly faster-than-expected increase in ice sheet warming, which could take place on the order of years to decades depending on the spacing of crevasses and other “pipes” that bring warmer water into the ice sheet in summer.
“The key difference between our model and previous models is that we include heat exchange between water flowing through the ice sheet and the ice,” said Rajaram.
Several factors contributed to the warming and resulting acceleration of ice flow, including the fact that flowing water into the ice sheets can stay in liquid form even through the winter, slowing seasonal cooling. In addition, warmer ice sheets are more susceptible to increases of water flow, including the basal lubrication of ice that allows ice to flow more readily on bedrock.
A third factor is melt water cascading downward into the ice, which warms the surrounding ice. In this process the water can refreeze, creating additional cracks in the more vulnerable warm ice, according to the study.

So the next time you have an opportunity to pee on ice, don’t be surprised if it reminds you of our world’s polar ice melt catastrophe.