It’s not uncommon, in scientific talks that have some vague relevance to climate change, for the speaker to say something like, “we need clean tech in order to address both the depletion of fossil fuels and the threat of climate change.” This isn’t an accurate picture of the situation we’re in, for a couple of reasons.
First, this is almost a contradictory statement. If it were true that we were running out of oil and coal, then mitigating climate change would probably solve itself. As supplies dwindled the prices of fossil fuels would soar and the transition toward electrification and wind and solar would happen automatically.
The second point is that it simply is not true that we are running out of fossil fuels.
See the gray curve on the “Reserves-to-production” chart here, which shows the ratio of total “proved” reserves against annual consumption. This tells you how many years we can keep consuming oil at the current rate, assuming no more reserves are discovered. But you’ll notice that this ratio (gray curve) has stayed pretty flat or even gone up since 1989. This even though annual global consumption has steadily increased over that time.
In other words: we tend to discover oil at a faster rate that we consume it, decade after decade.
Another point: “proved” by definition refers to economically recoverable reserves. If supply goes down and the price goes up, the quantity of “proved” reserves jumps automatically. This is the case for the infamous Canadian tar sands, for instance, which have a breakeven production price of around $50/barrel [link]. There is a lot of oil out there from which you can’t net a profit at the moment, which all of a sudden becomes a proved reserve when depletion of cheaper sources pushes up the price.
But it gets worse. Let’s say hypothetically that we really do have only 50 years of petroleum left, period. We would still be able to use fossil fuels for many decades more, by converting coal to liquid fuels and methane.
This is called coal gasification. And it’s easy as pie. Though it requires extra energy input (which can just come from the coal itself), it can be used as the main step in replacing any petroleum product. If you want, you can use coal to synthesize natural gas, gasoline, and jet fuel.
This is a concern because at current global consumption rates, and again ignoring any new coal deposits that would certainly be discovered, we won’t run out of coal for well over 100 years, and likely much much longer.
That we might theoretically eventually run out of fossil fuels is completely irrelevant, because we will never get to that point. The question is whether we’ll stop before reaching 2°C or 2.5°C or 3°C or even 6°C. At some point, climate disasters will force us to stop burning this stuff, but hopefully we won’t wait too long.
As I mentioned in the beginning, if we were running out of fossil fuels then this would not create an energy crisis, because it would simply shift the economics to favor low-carbon energy. But in any case, we’re nowhere close to running out. We should be so lucky. And if we do wait until coal and oil run out, the planet will already have warmed enough to destroy civilization.
Climate change (not fossil depletion) is the sole justification for the energy transition.