Normally, speculation drives up commodity prices by promoting hoarding. Yet there’s no sign of resource hoarding in the data: inventories of food and metals are at or near historic lows, while oil inventories are only normal.

Image Paul Krugman Credit... Fred R. Conrad/The New York Times

The best argument for the second view, that the resource crunch is real but temporary, is the strong resemblance between what we’re seeing now and the resource crisis of the 1970s.

What Americans mostly remember about the 1970s are soaring oil prices and lines at gas stations. But there was also a severe global food crisis, which caused a lot of pain at the supermarket checkout line  I remember 1974 as the year of Hamburger Helper  and, much more important, helped cause devastating famines in poorer countries.

In retrospect, the commodity boom of 1972-75 was probably the result of rapid world economic growth that outpaced supplies, combined with the effects of bad weather and Middle Eastern conflict. Eventually, the bad luck came to an end, new land was placed under cultivation, new sources of oil were found in the Gulf of Mexico and the North Sea, and resources got cheap again.

But this time may be different: concerns about what happens when an ever-growing world economy pushes up against the limits of a finite planet ring truer now than they did in the 1970s.

For one thing, I don’t expect growth in China to slow sharply anytime soon. That’s a big contrast with what happened in the 1970s, when growth in Japan and Europe, the emerging economies of the time, downshifted  and thereby took a lot of pressure off the world’s resources.

Meanwhile, resources are getting harder to find. Big oil discoveries, in particular, have become few and far between, and in the last few years oil production from new sources has been barely enough to offset declining production from established sources.