Opinion Scientists returning from a seaborne expedition to the Arctic say that the ongoing panic in some quarters regarding runaway emissions of methane from the chilly polar seas - and associated imminent global-warming disaster - appears to be unjustified.
For those unacquainted with this particular panic, the idea is that rising Arctic sea temperatures caused by humans in recent times are causing methane locked up as hydrates on the chilly seabed to be emitted into the atmosphere as gas – as methane hydrates are only stable at very low temperatures and high pressures. Methane, as any fule kno, is a hugely more powerful greenhouse gas than CO2, so this would cause more warming which would then release more methane from the seabed until once again planet Earth becomes a baking lifeless hell. As ever with scenarios leading to baking lifeless hell, the hippies* at Greenpeace and similar activists are very keen on this idea. Various scientists have detected methane emissions from Arctic waters by various means, too.
Anyway, this seemed worth looking into, so an international team of scientists set out this past summer aboard a German research vessel for the freezing seas off Spitzbergen, to look into Arctic seabed methane emissions and try to figure out what might be causing them.
In short, whatever it is, it doesn't seem to be anything human beings have done. The Arctic seems to have been emitting methane for a very long time. The Helmholtz-Zentrum für Ozeanforschung (Centre for Ocean Research, aka GEOMAR) in Kiel tells us so, in an announcement revealing the "surprising result" that methane emissions from the Arctic seabed are "no new thing".
“Details will only be known in a few months when the data has been analysed; however the observed gas emanations are probably not caused by human influence," says Professor Doktor Christian Berndt, the expedition leader.
Berndt and his colleagues believe this because their examinations of the seabed - conducted in part with the help of an undersea lab positioned in the area previously by a British research ship, and also with their own remotely operated submersible - show that the methane sources there have been in action for centuries. They have not suddenly appeared in response to the warming seen in recent decades, generally thought to have been driven by humanity's carbon emissions.
The GEOMAR statement says bluntly:
Above all the fear that the gas emanation is a consequence of the current rising sea temperature does not seem to apply.
“At numerous emergences we found deposits that might already be hundreds of years old. This estimation is indeed only based on the size of the samples and empirical values as to how fast such deposits grow. On any account, the methane sources must be older," adds Berndt.
This picture was also confirmed by the presence of large numbers of methane-gobbling microbes.
“Methane consuming microbes grow only slowly in the seabed, thus their high activity indicates that the methane has not just recently begun effervescing," explains Professor Doktor Tina Treude, another of the expedition scientists.
The GEOMAR statement can be read in PDF here. ®