A Possible Explanation of the Waste Heat Obsession
One of the favorite hobbies of Malthusians is to try to derive a reason why Population Growth Must Stop from first principles. The analysis is written down on the proverbial back of an envelope, which is then passed from environmentalist to environmentalist without coming in contact with reality.
One of the most obvious attempts was the use of the Second Law of Thermodynamics, which can be misinterpreted to say everything must decline. In a more sophisticated use, it says that, in a closed system, heat will accumulate. (Never mind, that the Earth isn't a closed system.) I suspect John Holdren's belief that heat is a major global problem (mentioned here) came from that. I recall that the first objections to nuclear power plants came from people worried about “thermal pollution.” in roughly the same era. It petered out when Jeremy Rifkin published Entropy, a New World View and exposed it to public scrutiny.
There are other attempts. In 1959, Isaac Asimov wrote an essay “Life's Bottleneck” in Fantasy & Science Fiction (reprinted in Fact and Fancy) about the danger of the world's supply of phosphorus washing into the sea. (In the real world, phosphorus is the 12th commonest element in the Earth's crust and can be easily recycled from bullsh!t anyway.) This has been passed from one self-congratulatory environmentalist to another for years.
There's also the claim that if we expand at an exponential rate long enough, the space occupied by human bodies will be expanding faster than the speed of light. Of course, in that case, time dilation will reduce the rate of growth. (I intend to post an analysis of this in a day or two, complete with differential equations.)
Addendum: The above-mentioned analysis is up.