It’s been some time since I created[1] and displayed the current atmospheric methane graph from the NOAA site, so here it is:
As you can see, the current surge in methane levels, which began in late 2006, is still going strong.
One thing that prompted me to post this was the appearance in my news feeds this morning of an article on that recent “250 plumes of undersea methane” study that was published recently.
Greenhouse gas leaking from Arctic Ocean floor:
Scientists have reported the presence of previously unknown sources of methane-a greenhouse gas some 25 times more powerful than CO2 at trapping heat-bubbling up from the Arctic Ocean seafloor north of Norway. Gradual warming of a regional current has caused temperature-sensitive methane hydrate below the seabed to break down and discharge the gas, the researchers say.
For years, scientists have debated whether the planet’s rising temperatures would turn methane deposits in permafrost regions into a “ticking bomb” that, once detonated, could liberate vast quantities of methane to the atmosphere, possibly triggering disastrous climate-feedback effects. Some paleoclimate studies have argued that such scenarios have occurred in the past, and that the processes of hydrate formation and disintegration have been a primary driver of glacial cycles.
Over the past couple of decades, as the tools for oceanographic exploration have grown more sophisticated, researchers have documented about 90 oceanic locations of methane hydrate, estimated to contain as much as 63,000 gigatons or more of carbon. Previously, International Polar Year (2007) surveys of the East Siberian Arctic shelf uncovered abundant methane seeps and measured record-breaking summertime concentrations of the gas in northern polar waters.
Where does this leave us? In short, the same place we have been for some time:
- We’re measuring more methane in the atmosphere, and it’s rising at a pretty swift, but not unprecedented, rate. Look at the graph and you can see other long run-ups, just since the late 1980′s.
- It’s still too early to state definitively where that methane is coming from. It could be rice cultivation and livestock, or it could indeed be the permafrost/hydrate bomb going off.
- The evidence, such as the study mentioned above, is leaning toward the bad news end of the spectrum. It could be that the additional methane is coming from entirely non-threatening sources (like crops and livestock and land fills), and that we’re just now discovering how much methane seepage from undersea sources is “normal”. And it could be that we’ve found a smoking gun in the form of those and other documented methane releases, and the slow-motion bullet that it fired simply hasn’t reached us yet.
- Arctic methane is still the monster under our collective bed.
[1] I can’t give you a direct link to this graph (because one doesn’t exist), but I can tell you how to recreate it on your own:
- Go to the web page http://www.esrl.noaa.gov/gmd/ccgg/iadv/
- In the “4. Gas” drop-down, select “CH4″ (which is methane).
- Click the “Submit” button. A version of the graph above will appear in a few seconds.
- Click on the link in the text “Click here to customize graph”.
- Click on the data set name, “MLO CH4 obs data (3397 masl)”.
- Under “Data Symbol”, set the type to “none”, and set the line widths and colors as you like. (I used a width of 6, and set the “Smooth Curve Line” to blue and the “Trend Curve Line” to red.)
- Click the “Set” button, which will take you back to the prior screen, then click “Get Plot” and wait a few seconds.
