Mason Inman - science journalist

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my recent articles
CO2 rise continues, but check out methane

14 May 2008, for New Scientist's Environment blog

A couple of headlines on Tuesday (here and here) reported that world carbon dioxide levels have set a new record, reaching the highest levels in 650,000 years.

This is a good reminder of what people are doing to the planet, but hardly news.

For decades, every year has seen a new record high of CO2, as shown by the annual annoucements from the US National Oceanic and Atmospheric Administration. As Science reported in 2006:
"At no time in at least the past 10 million years has the atmospheric concentration of CO2 exceeded the present value"
And judging from the data on the website of Yale's Mark Pagani, it looks like it has been about 20 million years since CO2 levels were as high as today's.

The gas just keeps building up.

What is new about the NOAA's greenhouse gas report this year is that methane levels also showed a clear increase for the first time in a decade.

Methane is a potent greenhouse gas, warming the planet 25 times more, molecule-for-molecule, than CO2. It doesn't last as long in the atmosphere, which tempers its kick, but it's still enough to give you nightmares.

As Fred Pearce has reported, thawing Arctic permafrost could give off massive amounts of methane, which would warm the planet. Permafrost is basically frozen mud, and when it thaws, microbes start chewing it up, emitting both methane and CO2, the amounts depending on the temperature, how wet it is, and other factors.

Either way, the released greenhouse gases could cause a positive feedback, with the thawing releasing greenhouse gases, which cause more heating, which cause more thawing.... With the recent increase in methane, we might be seeing the very beginning of this process, but at this point it's hard to say. According to a press release from NOAA that triggered the recent coverage:
Rapidly growing industrialization in Asia and rising wetland emissions in the Arctic and tropics are the most likely causes of the recent methane increase, said scientist Ed Dlugokencky from NOAA's Earth System Research Laboratory. "We're on the lookout for the first sign of a methane release from thawing Arctic permafrost," said Dlugokencky. "It's too soon to tell whether last year's spike in emissions includes the start of such a trend."

If you want to keep tabs on all these gases yourself, check out NOAA's Interactive Atmospheric Data Visualization. You can select from different stations, gases, and so on to produce your own customised charts. Or, for a longer-term graph of CO2, click here.

 

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