I just stumbled on a discussion of this document which was put out by Kissinger during the Nixon presidency. It shows that already in the 1970's they were aware of an impending population explosion and the expected resource competion in the future. The following gives a flavor of what was discussed regarding Resource demand ,
$this->bbcode_second_pass_code('', 'non-fuel minerals on which the U.S. depends heavily for imports1/ support these conclusions on
physical resources (see Annex). Proven reserves of many of these minerals appear to be more
than adequate to meet the estimated accumulated world demand at 1972 relative prices at least to
the end of the century. While petroleum (including natural gas), copper, zinc, and tin are
probable exceptions, the extension of economically exploitable reserves as a result of higher
prices, as well as substitution and secondary recovery for metals, should avoid long-term supply
restrictions. In many cases, the price increases that have taken place since 1972 should be more
than sufficient to bring about the necessary extension of reserves.
These conclusions are consistent with a much more extensive study made in 1972 for the
Commission on Population Growth and the American Future.2/
As regards fossil fuels, that study foresees adequate world reserves for at least the next
quarter to half century even without major technological breakthroughs. U.S. reserves of coal and
oil shale are adequate well into the next century, although their full exploitation may be limited
by environmental and water supply factors. Estimates of the U.S. Geological Survey suggest
recoverable oil and gas reserves (assuming sufficiently high prices) to meet domestic demand for
another two or three decades, but there is also respectable expert opinion supporting much lower
estimates; present oil production is below the peak of 1970 and meets only 70 percent of current
demands.3/ Nevertheless, the U.S. is in a relatively strong position on fossil fuels compared with
the rest of the industrialized world, provided that it takes the time and makes the heavy
investments needed to develop domestic alternatives to foreign sources.')
It seems reasonable that with time the trend of population growth, resource demand/supply must have been followed and at some point alarm bells began to start ringing. A triple alarm must have been sounded when Cheney put together his Energy Task Force as what was discussed is still secret.
Task Force
Google "nssm 200 " to find more.

