Over the past few days, observations of anomalously high methane readings have been coming in from Barrow Alaska. These four reading show a jump of ground level methane concentration at Barrow to 2090-2140 parts per billion (ppb). This is a massive increase over previous measurements of around 1890 ppb. You can see these readings in the graph above in the form of four orange dots in the far upper right hand of the graph.
Barrow is just one reporting station around the Arctic. So, in order to validate any large pulse in methane, we would have to see high readings around the Arctic. As yet, this doesn’t appear to be happening.
In addition, sometimes methane data gets corrupted by bad sensors or faulty process. The result can be anomalously high readings. This has happened before and there is good reason to suspect that these high readings could be caused by a failure of the methane monitoring process.
All that said, this year has seen a number of very strong global warming signals in the Arctic. We’ve seen record warmth over much of the region. We’ve seen record sea ice melt and a trend that shows a potential for ice free Arctic seas within ten years. And we’ve seen an immense increase in melt over the Greenland ice sheet. The sea ice melt is particularly troubling because it is occurring in weather conditions that should not be conducive for melt. And what this points to is a lot of latent heat in the Arctic doing the melting.
So given this context, it would be very unwise to ignore an anomalously high set of methane readings at Barrow. The reason is that heat can destabilize frozen sea bed or tundra methane and result in large pulses of methane hitting the atmosphere. These pulses can contribute large volumes of methane that can dramatically increase atmospheric concentrations. In addition, the over-all trend in the satellite record over the last ten years is for increasing pulses of methane emitted from the Arctic from September to January. Each year, the methane signal has been stronger, so this trend is also cause for concern.
It is still likely that these numbers are the result of error or faulty equipment. But there is a small but not insignificant possibility, perhaps a 20 or 30 percent chance, that this pulse showing up in the Barrow data is real. The fact that four observations are now showing anomalously high readings and that these readings are continuing to rise is serious cause for concern and needs close monitoring.
A large methane pulse in the Arctic this year would be a terrible result. It would add an amplifying global warming feedback to the already strong feedback of sea ice loss and loss of Greenland reflectivity. It would also show that the Arctic environment and the methane stores there are far more sensitive to temperature changes than most scientists had expected. So these observations at Barrow are serious cause for concern.
I got a response from Andy Crotwell a NOAA scientist specializing in greenhouse gas emissions. He notes that the wind on the day these samples were taken was likely from a developed area where methane readings would have been higher. So he’s pretty sure these are not representative of the Arctic environment and will be listed as outliers in the data.