Scientists have their own way of putting things. This is how Oerjan Gustafsson of Stockholm University announced the approach of a climate apocalypse in an e-mail sent last week from the Russian research ship, Jakob Smirnitskyi, in the Arctic Ocean: “We had a hectic finishing of the sampling programme yesterday. An extensive area of intense methane release was found. At earlier sites we had found elevated levels of dissolved methane. Yesterday, for the first time, we documented a field where the release was so intense that the methane did not have time to dissolve into the seawater but was rising as methane bubbles to the sea surface.”

Gustafsson’s preliminary report is a development far more frightening than the current financial crisis. The worst that the financial crisis can bring is some years of recession. The worst that massive methane releases can bring is irreversible global warming.

Methane gas is 20 times more potent than carbon dioxide as a warming agent. However, since methane doesn’t stay in the atmosphere as long — around 12 years, compared to a hundred years for CO2 — and human activities do not produce all that much of it, concerns about climate change have mostly been focussed on CO2. The one worry was that warmer temperatures might cause massive releases of methane from natural sources.

There are thousands of megatonnes of methane stored underground in the Arctic region, trapped there by the permafrost (permanently frozen ground) that covers much of northern Russia, Alaska and Canada and extends far out under the seabed of the Arctic Ocean. If the permafrost melts and methane escapes into the atmosphere on a large scale, it would cause a rapid rise in temperature — which would melt more permafrost, releasing more methane, cause more warming, and so on.

Now or never

Fear of this runaway feedback is why most climate scientists (and the European Union) have set a rise of 2 degrees Centigrade in the average global temperature as the limit which we must never exceed. Unfortunately, the heating is much more intense in the Arctic region. The average global temperate has only risen 0.6 ° C so far, but the average temperature in the Arctic is up by 4° C. So the permafrost is starting to melt, and the trapped methane is escaping.

That is what the research ship has just found. What this may mean is that we have no time left if we hope to avoid runaway global warming — and yet it will obviously take many years to get our own greenhouse gas emissions down. So what can we do?

There is a way to cheat, for a while. Several techniques have been proposed for holding the global temperature down temporarily in order to avoid running into the feedbacks. They do not release us from the duty of getting our emissions down, but they could win us some time to work on that task without running into disaster.

The leading candidate, suggested by the Nobel-winning atmospheric chemist, Paul Crutzen, in 2006, is to inject sulphur dioxide into the stratosphere in order to reflect some incoming sunlight. (This mimics large volcanic eruptions, which also lower the global temperature temporarily by putting huge amounts of sulphur dioxide into the upper atmosphere.)

Another, less intrusive approach is to launch fleets of unmanned, wind-powered, satellite-controlled vessels to spray seawater up into low-lying marine clouds in order to increase the amount of sunlight that they reflect. The attraction of this technique is that if there are unwelcome side-effects, you can turn it off right away.

Starting now, we need a crash programme to investigate the feasibility of these and other techniques for geo-engineering the climate. Once the thawing starts, it is hard to stop, so we may need them very soon.