I agree with the general sentiment, but their point here (as I understand it) is to show that the current trend cannot continue like this. The source paper has a poor choice of word in an appendix, saying "when the energy required for computing will exceed the estimated world’s energy production" with "will" instead of "would", but it's clear from the text they don't believe this. The next sentence is: "Thus, radical improvement in the energy efficiency of computing is needed".