A STRANGE ghostly light can appear over bogs at night.
"Ignis fatuus", or "foolish fire", seems to vanish as you approach it.
"Will o the Wisp" and "Jacky Lantern" are its common names. Jacky made a pact with the Devil; like Faust, he traded his soul for favours. In return, the Devil gave him a burning coal so that he could lure foolish travellers to their deaths in swamps.
Probe the muddy bottoms of stagnant pools and bubbles of "marsh gas" will rise to the surface. Hold a match close to the water and the gas will burn with a bright yellow flame. It’s mostly methane but there may also be phosphine, a compound of hydrogen and phosphorus which emits a faint glow when exposed to the air; "phosphorescence".
Although no supernatural agency is at work, marsh gas has some devilish properties, according to Katey Walter Anthony of the University of Fairbanks, Alaska.
Writing in the December edition of Scientific American, she claims that, by the end of the century, methane emitted from Arctic permafrost could increase global greenhouse gas levels by 20-40% over those coming from all other natural and man-made sources.
Permafrost, the permanently frozen soil of Arctic regions, covers a fifth of the Earth’s land surface.
During previous episodes of global warming, plants and animals thrived in the Arctic. Conifer and birch forests covered the landscape.
There were woolly mammoths, rhinos and big cats. When these plants and animals died, their remains became entombed in the frozen ground.
It’s estimated that about 950 billion tonnes of carbon are locked up in the permafrost.
This presents no threat to the environment as long as ground temperatures stay below zero degrees but now, with the onset of global warming, the permafrost is thawing.
As the ground softens, bacteria begin to devour the ancient organic deposits, releasing carbon dioxide as they do so. A bacterial population explosion follows but soon the oxygen in the soil runs out. Anaerobic, or non-oxygen-dependent, microbes take over. These produce methane, 25 times more potent as a greenhouse gas than carbon dioxide.
Releasing large quantities of methane into the atmosphere, as the rumens of Ireland’s eight million cattle do, accelerates the process of climate change.
Permafrost melting is a self-regenerating process; the released methane leads to further warming which in turn causes more thawing, an avalanche effect. Analysis of the gas bubbles trapped in Arctic ice cores shows that methane levels in the atmosphere have increased by 160% since 1700.
Polar regions are warming faster than the rest of the planet.
Walter Anthony and her colleagues have been monitoring environmental changes in Siberia and measuring the amounts of gas released from the bottoms of Arctic lakes. Her findings are startling.
The permafrost thaw is accelerating. One-third of the soil, she claims, is now between 1C and 1.5C below the point at which it will begin to thaw. If trends continue, the carbon released from the permafrost will add 0.32C to the Earth’s temperature this century.
Walter Anthony’s results are corroborated by other studies.
A paper, published in the journal Science, looks at findings obtained from satellites monitoring groundwater depths. Changes in depth correlate with methane emissions and the satellite data indicate that there has been an increase in methane emission of 31% over five years. This is an ominous finding but the scientists, ever cautious, consider that the study period is too short for firm conclusions about long-term trends.
Half of all methane emissions come from the tropics.
The Arctic accounts for only 2%. It’s tempting to think, therefore, that thawing of the permafrost is not such a significant problem.
However, if current trends continue, the gases released in the Arctic will be enough to undo all human efforts to curb climate change. The only way we can prevent this from happening is to reduce our carbon emissions now so that thawing of the permafrost is halted.
a d v e r t i s e m e n t
This appeared in the printed version of the Irish Examiner Monday, January 25, 2010
