This article is, frankly, statistical malpractice. Limits of Growth predicted continuations of historical trends followed by sharp reversals; the data in this article shows that historical trends have continued, and the authors conclude that the sharp reversal must becoming soon. You could confirm any model you wanted that way.

The peak oil discussion is especially anti-prescient, because innovations since this article was written have made both oil and renewable energy much more available. It's generally acknowledged nowadays that demand for oil will peak long before the supply starts to run out.