Methane Hydrate: Friend or Foe?

I quote James Howard Kunstler a lot in these entries. Kunstler’s book, The Long Emergency, introduced me to the subject of Peak Oil. In one part of the book, Kunstler goes through a list of alternative energy sources, and systematically crushes all hope for ways to avoid the impending catastrophe. Here’s his take on methane hydrate:

This is a kind of “ice” consisting of methane molecules, each surrounded by a “cage” of water molecules, stable only at low temperatures and extreme pressures typical of water depths below about a thousand feet. They do represent a possible recoverable energy resource, but with important reservations. One is that methane hydrates are very difficult to recover, meaning expensive, meaning they may require more energy to get than they produce when recovered, meaning they would be basically uneconomical. In fact, to date exactly zero methane hydrates have been commercially recovered.

Methane hydrate is also hazardous. Attempted underwater “mining” operations so far have led to explosions, including the destruction of drilling platforms and ships. The physical properties of methane hydrate are such that any attempt to recover them tends to wildly destabilize the material, causing the water and methane to dissociate. The freed highly flammable gas then rises to the surface. Industry has concerns about drilling through hydrate zones, which can destabilize supporting foundations for platforms. The disruption to the ocean floor also could result in surface slumping or faulting, which could endanger work crews and the environment. In addition to posing danger to humans attempting to mine it, methane freed into the atmosphere is a ten times more effective greenhouse gas than carbon dioxide. Released in any quantity, it would accelerate the problem of climate change. So far, attempts to recover methane hydrates have resulted in releases of methane into the atmosphere proportionately much greater than the gas recovered in the process.

Kunstler is by no means the last word on these subjects. More about that soon. Methane hydrate is an alternative energy source, and we need alternatives. It’s not feasible yet, but let’s not give up.

Extinction Level Events

Another name for methane hydrate is methane clathrate. Methane buried as ice in sea beds can be released when the ocean warms. According to the clathrate gun hypothesis, a release of methane would have catastrophic effects on the atmosphere. CH4 (methane) is a powerful greenhouse gas. If the oceans warm enough, the runaway greenhouse effect would be terrible. I guess that’s why scientists refer to it as a gun.

It’s possible that such a release was responsible for the Permian mass extinction. That’s not what killed the dinosaurs and 60% of life on Earth. The Permian extinction took place 250 million years ago and killed off 95% of life on our fragile little planet.

When Paul Wignall learned of [geologist Gerry] Dickens’ findings [about rising sea temperatures and releases of methane hydrate], he used his carbon-12 data to estimate how much methane hydrate would have to be released to affect the isotope balance. Methane is one of the most potent greenhouse gases and he deduced that unlocking frozen methane hydrate would have caused a temperature rise of 4-5°C over time. Not enough to kill off 95% of life on Earth but he realised this was a compounded effect. A rise of about 5°C must already have occurred to prompt the frozen methane to melt. The combined temperature rise of 10°C is generally accepted as a figure able to cause truly mass extinction.

Nothing like a little end-of-the-world scenario for a sunny Friday the thirteenth after an unusually hot few days in late spring, to distract me from that depressing Peak Oil story!

But methane hydrate is not just an excellent greenhouse gas, it’s also extremely flammable. In 2003, Northwestern University’s Gregory Ryskin published a different theory about Methane-driven oceanic eruptions and mass extinctions.

The consequences of a methane-driven oceanic eruption for marine and terrestrial life are likely to be catastrophic. Figuratively speaking, the erupting region “boils over,” ejecting a large amount of methane and other gases (e.g., CO2, H2S) into the atmosphere, and flooding large areas of land. Whereas pure methane is lighter than air, methane loaded with water droplets is much heavier, and thus spreads over the land, mixing with air in the process (and losing water as rain). The air methane mixture is explosive at methane concentrations between 5% and 15%; as such mixtures form in different locations near the ground and are ignited by lightning, explosions and conflagrations destroy most of the terrestrial life, and also produce great amounts of smoke and of carbon dioxide. Firestorms carry smoke and dust into the upper atmosphere, where they may remain for several years (Turco et al., 1991); the resulting darkness and global cooling may provide an additional kill mechanism. Conversely, carbon dioxide and the remaining methane create the greenhouse effect, which may lead to global warming. The outcome of the competition between the cooling and the warming tendencies is difficult to predict (Turco et al., 1991; Pierre-humbert, 2002).

We need to harness this stuff before it kills us. Have a great weekend!