Methane

Methane is in the news at the moment for many reasons. Perhaps first is Obama’s plan to reduce CO2 output by 30% by 2030 by reducing coal consumption and increasing the use of natural gas at our power plants. When natural gas burns it produces about half the CO2 that coal does when it burns (for the same amount of heat/power output) so this seems like a big win. Unfortunately it has several problems:

  1. Natural gas is a gas. It leaks. It leaks everywhere. At wells, in pipelines, in processing facilities. No one knows how much it leaks. You might wonder why this matters, but over 100 years a given amount of natural gas will trap 20 times as much heat (cause 20 times as much global warming) as the equivalent amount of CO2. So seemingly small leaks can spell disasters. A recent article by Scientific American concludes that even if fully implemented Obama’s plan would not achieve its goal of a 30% reduction by 2030.
  2. Although we currently have a glut of natural gas that is likely to be temporary. Current projections say that shale gas production in the US will probably peak around 2015 (next year!) and decline steeply thereafter. Relying on it is stupid.
  3. Switching to natural gas will not be cheap. And that infrastructure will still be here in 20, 30, 40 years time. Unfortunately in 40 years time we cannot use it. Natural gas still produces far too much carbon. We need to get our carbon consumption down by more like 80% by 2050, and if we invest heavily in natural gas we will have a bunch of useless expensive junk in 40 years time.

A far better solution would have been to invest heavily in renewables, but that seems to be politically infeasible. Of course even reducing coal usage also seems politically infeasible so perhaps it would have been better to bite the bullet and try for something that might ultimately work…

Another interesting new story is about the recent discovery of mysterious new craters in the Siberian tundra. Three large craters have recently been found. The one which has been examined most closely was probably caused last summer (2013) when the underground methane hydrates heated up to the point where the methane came out of solution, expanded and exploded the ground above it. But there are only three craters, and that was last year.

At approximately the same time as that discovery a Swedish research vessel in the Arctic Ocean found plumes of methane gas bubbling up from 500m subsurface. This should not be happening in the Arctic, the water should be cold enough to trap the gas in hydrates. Even if it were happening the gas should be eaten by microbes before it reached the surface. But it appears that an underwater warm current is now melting the methane hydrates and releasing the gas.

One of the great imponderables (or “tipping points”) in climate sciences was if or when the methane hydrates in the tundra and oceans would release their methane. The problem is that there is an awful lot of methane trapped in these hydrates. Remember methane is a very potent greenhouse gas? The fear is that once methane starts leaking it will cause the earth to get warmer, which will cause more methane to leak, leading to a positive feedback loop where there is exponential heating as all the methane hydrates disappear.

The terrifying thing about passing a tipping point is that once passed there is absolutely nothing that can be done (on a human timescale) to return the world to its prior state. Even if we stopped burning any coal or oil or methane it would not be enough. If this is happening, we are screwed.

No one really knows how much hotter it will get. Nor how fast it will happen. The IPCC has not included this in their estimates.

But the process now seems to have begun. We will find out. Perhaps quickly (where “quickly” may mean decades or even years rather than the centuries that the IPCC has assumed we have).

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One Response to “Methane”

  1. Martin Says:

    Of course, if it were not a finite resource it would probably be the fuel of choice for power stations. But it is, so using CH4 to generate electricity doesn’t make too much sense to me either. For a start, it is easily piped into people’s homes etc where it can be converted into heat very efficiently – power plants achieve something like 40% efficiency.

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