Gas or coal? The quandary, the indecision!

Well, now we have a peer-reviewed scientific paper that says you can.

It’s hard to know what to say about Tom Wigley’s new paper on the climatic repercussions of replacing coal with natural gas: he says gas and coal are both good, and they’re both bad, but the truly remarkable thing is that, where for years the greens have been telling us to hate coal and everyone who uses it, now it’s hard to choose between coal and gas.

It doesn’t matter whether you believe mankind is warming the planet dangerously or not, Wigley tells us that it makes hardly any difference to the warming whether you use gas or coal. So why switch to gas? There’s no advantage in it.

In 150 years the advantage of gas in reducing global temperature would have grown to about 0.2°C — still minuscule; in the environment, undetectable — and even that change will be purchased at huge expense.

It slashes the greens’ arguments to ribbons. We need no longer listen as they praise natural gas and excoriate coal for its dangerously warming emissions, because the difference between them is indistinguishable — staying with coal makes the world by 2050 only 0.02°C warmer. If we make the expensive change to gas, after one hundred years, it’s still only 0.1°C cooler than coal. Completely undetectable.

(Those figures are approximate, derived by running a ruler over Wigley’s graph of the net effect of a 5% leakage of methane. Try it yourself here — link further down.)

Fig. 3 The effects of different methane leakage rates on global mean temperature. The top four curves (CH4 COMPONENT) show the effects of methane concentration changes, while the bottom four curves (TOTAL) show the total effects of methane changes, aerosol changes and CO2 concentration changes. The latter two effects are independent of the leakage rate, and are shown in Fig. 2. Results here are for a climate sensitivity of 3.0°C.

The global warming effects of the two methods of obtaining energy are very similar. There are more real pollutants from coal, so we need modern installations to keep the air clean, but we don’t need to quit coal with the religious zeal of the greens. Or the expense or the haste.

In fact, Hansen can go hang; his “coal trains of death” are the exaggerated product of an imagination gone beyond reality.

But a fresh new peer-reviewed scientific paper says coal is indistinguishable from gas in regards to global warming. So please reconsider your advice — it threatens to make things very expensive.

The paper, Coal to gas: the influence of methane leakage, published in August in Climatic Change Letters, re-examines the effects of changing from coal to natural gas to produce energy.

It’s been done before by Hayhoe et al. (2002) but since then we’ve invented fracking to get at the gas in shale beds. Fracking will tend to allow a little more methane leakage than conventional gas production. The scientists wanted to investigate that because of the relatively enormous global warming potential (GWP) of methane over carbon dioxide.

The GWP of methane is a matter of some dispute elsewhere on this blog.

The paper uses models more than measurements and of necessity makes assumptions about the future so there must be sizeable uncertainties but there is an interesting discussion at the end (emphasis added).

In our analyses, the temperature differences between the baseline and coal-to-gas scenarios are small (less than 0.1°C) out to at least 2100. The most important result, however, in accord with the above authors, is that, unless leakage rates for new methane can be kept below 2%, substituting gas for coal is not an effective means for reducing the magnitude of future climate change. This is contrary to claims such as that by Ridley (2011) who states (p. 5), with regard to the exploitation of shale gas, that it will “accelerate the decarbonisation of the world economy”. The key point here is that it is not decarbonisation per se that is the goal, but the attendant reduction of climate change. Indeed, the shorter-term effects are in the opposite direction. Given the small climate differences between the baseline and the coal-to-gas scenarios, decisions regarding further exploitation of gas reserves should be based on resource availability (both gas and water), the economics of extraction, and environmental impacts unrelated to climate change.

What a turnaround.

I expect the Hockey Team will turn on Professor Wigley with a vengeance, and I don’t expect Greenpeace to endorse the study quickly.

PS: I’ve just refreshed my memory of Prof Wigley’s track record. Is this story the more remarkable because of his history of ultra-warmism? Do these findings change your perception of him?

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