Gaia Save Us! Not So Fast, part four. Gaia Burps!

This is the fourth in a series of essays about the Gaia Hypothesis.

I don’t mean burps like the one you just had. I mean, Gaia sometimes burps. I guess it depends on which way Gaia is facing. If she is facing the other way, it is not technically a burp.

This is number four in a series of essays about Gaia, which is the not-quite-alive not-quite-goddess system of feedback loops that keeps conditions on Earth stable, sort of.

These burps are methane burps. In shallow tropical seas, sediments accumulate with organic material. Sometimes this material becomes petroleum, but sometimes it becomes methane, or natural gas. When trapped inside of rock, natural gas can be extracted and used by humans. But when it is in loose sediments, as frequently happens in new deposits in shallow seas, it is simply held in place by the pressure of the water above it. Actually, the methane gas molecules are held inside of gels called clathrates created by water molecules.

Until one day when it isn’t, and the methane rushes out.

If the water becomes shallower, or less dense (due to global warming, for example), a critical point is reached when the first methane molecules begin to move, dislodging sediment particles, which allows other methane molecules to move…and before you know it you have a geyser of methane spewing out of the shallow water.

This is the explanation of the infamous Bermuda Triangle, which is an area of shallow sea between Bermuda and Florida. Pseudo-intellectuals such as the late Erich von Däniken imagined that it was outer space beings who made ships and planes disappear in the Bermuda Triangle, but it was actually just methane. Methane bubbles would disrupt the water and make ships sink, and the methane itself would displace the oxygen which the planes would need for combustion. Ships and planes would fall into the sediments without a trace.

Methane is a powerful greenhouse gas, much more potent than carbon dioxide. It will react with oxygen gas to become carbon dioxide, but this process takes about ten years. Meanwhile, the methane creates a powerful greenhouse effect. Much more important for the global climate is the slow release of methane bubbles from organic layers. You can see these bubbles in lakes over permafrost:

  

There were many shallow seas at the end of the Permian, and methane burps might have contributed to the general climatic chaos caused by the Siberian volcanoes and the surface area of Pangaea, especially as continents plowed through them on their apparently aimless course of drift.

Gaia has no mind and is slow. It may have saved Earth from becoming an ice planet or a hellish one, as explained in the first essay. But on a day to day, or million year to million year, basis, it is of little help to the planet.