Why did methane shoot up after a decade of holding steady?

Question

How would industrialization be implicated (as mentioned below)? Why are methane clathrates not mentioned (or was that just an omission in the news article)?

http://news.yahoo.com/s/ap/20080423/ap_on_sc/greenhouse_gases

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 Ed Dlugokencky from NOAA's Earth System Research Laboratory.

Methane in the atmosphere rose by 27 million tons last year after nearly a decade with little or no increase, he said.

Methane is 25 times more potent as a greenhouse gas than carbon dioxide, but there's far less of it in the atmosphere. When related climate affects are taken into account, methane's overall climate impact is nearly half that of carbon dioxide.

---

What was the prior level of methane?

What if methane clathrates are involved, could we be seeing the start of a positive feedback tipping point?

Answer 1

Yet despite the increase in Methane, temperatures fell last year world wide.  But then again that is proof that natural forces are a lot more powerful than increases in GHG.

By the way, I noticed that the article has fail to mention the levels of methane.  Could it be that they are so small that they are insignificant?

Answer 2

My guess its that it's due to methane releases from melting permafrost.

http://news.bbc.co.uk/2/hi/science/natur...

I recall reading that scientists were surprised methane levels didn't increase significantly in 2006 because they were observing methane bubbles in the permafrost.  So this isn't a surprising finding.  It is a concerning one though.

Methane level graph: http://www.noaanews.noaa.gov/stories2008...

Answer 3

Why did the methane concentration level off in the first place? We have no clue.

Regarding your last question, I find that unlikely, being that we have no real evidence that such an event has ever occurred. Mostly minor speculation and hypotheses.

So unless these clathrates are newly formed (in the past 500 years), then they have seen temperatures much warmer than now.

I would think that the change in atmospheric methane was likely due to natural fluctuations or perhaps land use changes (China?).

Edit:

The number 500 was an exaggeration for effect. It was meant as a way of explaining that the clathrates would have to be recently formed to have not seen temperatures warmer than today.

Regarding the P/T extinction, there is very little (emphasis on very little) evidence that a methane clathrate release was the cause. Meteor impact/volcanism is the other leading theory--similar to the running theory for the Cretaceous extinction. And why the current temperatures (much cooler than the mean for the last half a billion years) would destabilize these clathrates is beyond me.

If they are showing signs of instability, it is far more likely that a change in ocean currents is the cause rather than a small rise in ocean temperatures.