I was skeptical.

But ESA has come out to confirm the existence of methane
in the martian atmosphere detected by Mars Express.

So what does the confirmation of the existence of methane in the martian atmosphere mean?

(1) It means the detected methane has been in the martian atmosphere less than 300 years. [Without replenishment, methane can only survive
at most 300 years in that atmosphere]

(2) It does NOT PROVE that there is life on Mars today; but I confess
that it is compelling evidence for that hypothesis.

(3) It's MORE LIKELY that the methane had a volcanic [geothermal] origin.

(4) The discovery of methane in the martian atmosphere is, regardless,
a "win-win" situation; (a) It either proves there has been volcanic [geothermal] activity in the past 300 years on Mars; or, (b) there's life on Mars today; or, (c) there are buried CH4 clathrates on Mars decomposing upto the present time [I think this would be Nick's preferred hypothesis].

(By the way, Nick!...Don't give up on the idea of the existence of buried CO2 clathrates [as well as CH4 clathrates] existing on Mars today inspite
of the discovery of strong evidence for the existence of an ancient salty seas in the Meridiani area on Mars...In fact [I believe] a very-deep body of seawater, with dissolved CO2 in it, with heavy sediments settling out at the bottom, may generate sufficent pressure at its seabed to
help bring about the formation of CO2 clathrate deposits....That's my
opinion...But I defer to you, Nick....You're the expert.)

As for what happens to the methane once UV light breaks it down chemically in the martian atmosphere?...
[CH4 -> H2 + CH2; H2 + CH2 -> CH + 3H]
Didn't some of you post threads at the BBS site over the years, as well as here at HZ, where you claimed you could make out black streaks or "dark deposits" in some of the MGS images?...hydrocarbon tars?...pitch?
Hmmm...Interesting....

Jacob

"This planet has a 100 percent mortality rate."