Grist: What if there’s much less coal than we think?

How much coal is there in the world?

It’s tough to think of a more important question for the next half-century. The answer will play a huge role in shaping public policy and directing capital investments. So we’ve got it pretty well nailed down, right?

Turns out, maybe not.

The prevailing conventional wisdom is that the U.S. has a “200-year supply” of coal — sometimes jacked up to “400-year” by industry enthusiasts. If that’s true, there’s obviously an enormous incentive to build the infrastructure to keep using it. Such is the essential argument for carbon capture and sequestration: coal will always be abundant and cheap, so we “have to” keep burning it, so we have to find some way of burying its carbon pollution.

But what if we’re overestimating the amount of coal left? What if it’s actually going to get scarce and expensive in the near- to mid-term?

If that’s true, it has huge, huge implications. Two in particular:

1. If coal is soon going to get harder to reach and more expensive, an enormous investment in carbon capture and storage may not make sense. Remember, building the infrastructure necessary to run our economy on renewables and efficiency will itself be an expensive, energy-intensive undertaking. If our fossil-fuel savings are running low, we urgently need to spend every penny of that energy wisely. If we waste a huge chunk of it on CCS only to find coal drying up, we’ll have that much less to put toward building post-fossil infrastructure.

2. If there’s much less coal than widely assumed, climate change may not be humanity’s biggest problem. Most of the more dire IPCC climate change scenarios assume endlessly rising energy demand and use, and thus endlessly rising CO2 emissions. But those models tend not to pay heed to the physical world. If some of the new research on coal reserves is accurate, it is mathematically impossible to emit as much as the high-end IPCC scenarios. There just won’t be enough fossil fuels.

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