Thermodynamics does not imply near-term energy descent

Thermodynamics is a recurring theme in doomer literature. Doomer sites are filled with talk of thermodynamics, especially the second law of thermodynamics. This is not surprising, since borrowing terms from rigorous disciplines like physics could lend credibility to the doomer thesis. Also, the second law of thermodynamics does have a superficial rhetorical similarity to the doomer thesis insofar as it implies "decline" of some kind.

Quite frequently, doomers will claim that the laws of thermodynamics imply a near-term energy descent scenario ending in the collapse of civilization. After all, the second law of thermodynamics states that entropy is always increasing, and that energy gradients available to do work are always decreasing. Doesn't this imply that the net energy available to us to do work must always decrease, as a matter of inevitable physical laws? As usable energy decreases, mustn't civilization collapse?

For example, here is a quotation from the first few sentences of dieoff.org:

"Calculations show that conventional oil production 'peaked' in 2005, so it is now physically impossible (thermodynamics) to increase 'net energy' as we have in the past."

...and this kind of talk is extremely common in the doomer literature.

However, the doomer literature contains extremely grave misconceptions about what the laws of thermodynamics really claim. For example, the second law of thermodynamics states that energy of all kinds, including matter (which is convertible into energy), will tend to equilibriate, in an isolated system. Please note the bold portions of the prior sentence, since those parts are often forgotten or omitted in doomer accounts of the second law of thermodynamics. Thus, the second law of thermodynamics would imply doomer energy descent only if all three of the following conditions were met: 1) we lacked the technology to convert matter into energy; 2) the Earth were an isolated system; 3) fossil fuels were the only form of energy available to us. If all three of these conditions were true, then and only then would the laws of thermodynamics imply a doomer energy descent scenario, because then we would have no other possible sources of energy when fossil fuels are depleted. However, none of those three conditions is true. Specifically, matter can be converted into energy, so we can switch to nuclear power and more than offset a decline in fossil fuels¹. And, the Earth is not an isolated system, but is continually bombarded by energy from the Sun, so we could harness this energy and more than offset a decline in fossil fuels. Note that these alternatives are compatible with the laws of thermodynamics.

Of course, we'll still gradually "run out of energy", since the other sources of energy aren't infinite either. The second law of thermodynamics really does imply a long-term energy descent over many billions of years. The Sun will gradually dim over billions of years. Nuclear fuel will gradually be exhausted over millions of years (or billions of years, for fusion).

However, we don't face any kind of inevitable energy collapse over the next few centuries since fossil fuels are not the only kind of energy to which the laws of thermodynamics refer.

...

As our supplies of fossil fuels gradually diminish over the next 150 years, we will face several different options, as follows:

1. We could gradually transition to renewable sources of energy like wind power, solar thermal, and so on.
2. We could gradually transition to nuclear reactors, and then breeder reactors.
3. We could develop hot fusion as an energy source.
4. We could do nothing whatsoever about the situation, as the energy available to us declines gradually over decades or centuries, until civilization collapses and we revert to a tribal state.

The laws of thermodynamics are compatible with all these scenarios. Furthermore, the laws of thermodynamics provide no guidance whatsoever as to which of these scenarios will occur. This is an economic calculation problem, the answer to which cannot be derived from the laws of thermodynamics.

Also, please note that all of the above scenarios are sustainable in the long run. Whether we transitioned to renewable energy, or breeder reactors, or hot fusion, or neo-tribalism, we could continue along with our chosen strategy for hundreds of millions of years. Note that I'm not claiming we could increase our rate of energy consumption exponentially for hundreds of millions of years. I am claiming, however, that we could provide power to 10 billion people at a first-world standard of living for hundreds of millions of years.

In conclusion. The laws of thermodynamics provide no support whatsoever to the doomer thesis of imminent energy descent². Although doomers frequently invoke the laws of thermodynamics, those laws provide no support for their conclusions, unless we wrongly assumed that the Earth were an isolated system, that matter is not convertible into energy, and that fossil fuels were the only source of energy.

In fact, the laws of thermodynamics are compatible with a wide range of outcomes for civilization, including the outcome of sustained first-world living standards for a large, stable population for a very long time.

NOTES:
¹ Of course, this would require energy storage (like batteries) if we are to use nuclear power for cars. However batteries are compatible with the laws of thermodynamics and this point isn't really relevant here.
² Of course, the laws of thermodynamics do imply a long-term energy descent. Eventually, our Universe would face a "heat death" where entropy had reached its maximum. Before the heat death occurs, our Universe would face a situation where almost all usable energy had been exhausted and very little was happening. This would happen in about one quadrillion years. This kind of "energy descent" really is implied by the laws of thermodynamics. However the near-term energy descent featured in doomer literature is not at all implied by the laws of thermodynamics.