There have been quite a few articles and news items over recent months describing the climate change danger posed by methane clathrate. Methane clathrate is a special combination of methane molecules trapped within ice crystals – apparently it looks like dirty ice, feels like sorbet and bursts into flames when touched with a flame. Methane clathrate forms when organic matter decays and releases methane which permeates through rocks and ends up somewhere where the temperature is approximately 0 °C and the pressure is ~50 atmospheres. When this happens ice crystals form that trap the methane molecules. The required conditions occur underneath permafrost and on the seabed at depths of 200-400 metres.
Most of the articles I have read about methane clathrates focus on the concern that if permafrost warms up, the ice crystals may melt and huge amounts of methane (a very potent Greenhouse gas) may suddenly be released. That’s bad news for climate change, really bad news…
However, a recent article in New Scientist, Issue 2714 [27 June 2009] (and Editorial) suggests that it may be possible to extract the methane from methane clathrate fields and then use this as an energy source. So, we can replace our dependence on the fossil fuels of coal, oil and natural gas with a new dependence on a new fossil fuel – methane. I guess that it is better to use the methane productively than to simply warm up the world until it burps out into the atmosphere and, intriguingly, one of the methods being explored for extracting methane from clathrates is to pump carbon dioxide into the clathrate field where it displaces the methane. This means that we may be able to store carbon dioxide safely out of harms way (thereby limiting Greenhouse gas emissions) and at the same time produce a source of energy. Neat.
Actually, for some time I have been wondering (not seriously) whether methane clathrates were made by humans at some past time when we had a problem needing to dispose of Greenhouse gases such as methane in a safe and secure way. Back then, someone might have had a neat idea to pump methane into the permafrost and encourage clathrate formation, thereby removing the methane and helping to prevent past global warming… well, it’s not impossible.
Tim O'Hare 