Scientists studying remote Arctic seas north of Siberia have found  high levels of the powerful greenhouse gas methane, in some places bubbling up from the seabed. 

But is it new (extremely alarming as a possible sign of climate change), impossible to know how long it’s been going on (still worrying), or might it have been happening for a long time (less alarming)? Even the scientists involved seem unsure. 

In the worst case, the leaks are recent and caused by global warming — a thaw of the seabed permafrost linked to rising sea temperatures that could go on to release vast buried stores of the heat-trapping gas that would further stoke global warming. In the best case, it may have been going on for thousands of years in an inaccessible area where no one has taken measurements before.

Either way, it’s worrying because a projected rise in temperatures could further erode the permafrost that had previously been considered an impermeable cap and so lead to more releases of methane.

The article in the journal Science  makes clear that you can’t tell whether it’s new or not –more monitoring is urgently needed. 

The University of Alaska, where some of the scientists are based, put out two embargoed press releases. The original said the seabed is “starting to leak” (very alarming)

The second one, which replaced the first about a day before the embargo was lifted, changed the second paragraph to drop the word “starting” and merely say the seabed “is leaking” (worrying):

So let’s hope it’s been going on for ages.

(Photo top: The Advanced Microwave Scanning Radiometer, a high-resolution passive microwave Instrument on NASA’s Aqua satellite shows the state of Arctic sea ice on September 10, 2008)