Methane checkpoint

I had planned to write this up in a day or two, but after a quick look at the graphic Joe Romm included in his latest poke at climate chaos deniers (which you should read), I felt a bit more urgency.

The graphic in question is from the NOAA, and it shows the latest take on temperature trends around the world (click on this copy for a larger version in a new window):

See that mass of big, red dots in Russia? Those are the +5C readings, meaning an increase of that much over the 1961-1990 average. That’s where an immense amount of permafrost resides, which contains several times as much carbon as is currently in the atmosphere in the form of CO2. That’s the carbon pulse time bomb we keep talking about, the number one thing that has energy and enviro geeks (including yours truly) scared spitless. If it happens, it will mostly show up as atmospheric methane, which has a global warming potential of about 20 times that of CO2 over a 100-year time span.

So, one might well ask, what’s going on with the observed levels of methane?

If you check my graphs page, you’ll see this depiction of atmospheric methane levels:

Notice that the curve turns upwards right at the very end, which, inconveniently enough, only brings us to the end of 2007. It took a little digging to add more recent data, but here’s what I found.[1]

If you go here, you’ll find the Interactive Atmospheric Data Visualization tool provided by the NOAA’s Earth System Research Laboratory, which lets you create and customize graphs of various data sets. If you select “time series”, “ch4″, “obs data” in the drop-downs and click “submit”, you get a graph that’s frankly a little tough on the eyes thanks to the overlapping symbols and color selections. But on that page you can click a link to customize the graph, and on the ensuing page click on the data set (there’s only one) and then fiddle with the color and thickness of lines, as well as turn off the symbols for the individual data points. When I did that and used the same colors as the methane graph above, here’s what I got:

Please note a couple of things:

• I manually added the green, vertical line to mark the beginning of 2008, just to make it a bit easier to see what methane did last year and in the beginning of 2009.
• As best I can tell, this custom chart is based on data from just the Mauna Loa monitoring station, while the pre-made chart (the one that ends before 2008) uses data from all monitoring stations. I strongly doubt this will make a difference, as the red trend lines in both charts is virtually identical. (As you stare at them, you have to take into account the different vertical scales as well as the greater time range of the first chart.) I believe that the data for the main chart will be updated for post-2007 sometime later this summer.

What to make of this?

Most obviously, methane is continuing to rise. The red trend line is still rising, in nearly a straight line from the local minimum around the third quarter of 2006. Also, since that point in late 2006, the blue observations line has made two highs and two lows, each one successively higher than the high or low of 2006. In other words, the red trend line isn’t rising because of much higher highs and constant (or slightly lower) lows.

Is this the first wave of methane from the time bomb going off? It’s way too early to leap to that conclusion, even if we’d all feel a lot better if the 2008 data showed a decline instead of a continued rise. If nothing else, notice the sustained increases beginning in roughly 1987, 1992, and 1996; it could very well turn out in a few years that we’re merely ratcheting up another level, and that we’ll experience another one or two years of decline.

As for the pronounced stair step or saw tooth pattern in the observations, I have no idea what’s at work. I’m sure many other people, including some real climate experts, have noticed this and have some theories or even accepted explanations. I did a quick check online and couldn’t find any references to it.

For now, I think the best we can say is that methane is still rising noticeably, and then hope it’s not a sign of things to come from all that warming in the wrong places.

[1] Notice that since I can’t get a direct link to the final graph, I’ll tell you how to reproduce it on the site.