We have the puzzling fact that methane seems to be
much more concentrated (by factors of 10 or more)
over certain sites on Mars than in the general atmosphere.
Yet the 300 years that methane is estimated to survive
in the atmosphere is enough to spread it evenly over
the whole planet.

A possible explanation might be that the methane has
only recently been generated, perhaps due to contamination
by microbes from Earth delivered by 20th century space
probes. The Viking probes are apparently the only ones
that have been completely sterilized by baking in ovens.

This might also explain why measurements from the MGS
orbiter indicate that Mars appears to be getting warmer,
as judged by the recession of the southern polar cap over
the last 2 martian years. Methane is a greenhouse gas.

If this speculation is correct, then we can expect the
methane on Mars to increase dramatically over the coming
years, and we might also see a substantial warming.

Paul

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