In the case of oil, we know that supply has increased enormously in recent years, thanks to fracking technology. As the first chart above shows, U.S. crude oil production is up over 80% since late 2008. As the second chart shows, U.S. oil consumption has fallen over the same period. Since 2008, the U.S. has added over 4 mbd to the global oil market, while at the same time reducing its consumption of oil by about 2 mbd. The net effect has been to add upwards of 6 mbd to global oil supplies. This strongly suggests that the collapse of oil prices is almost entirely due to increased supply, rather than weaker demand, in which case lower prices are a blessing, and not a portent of disaster. With lower energy costs we are very likely to see stronger economies going forward.
And even though oil prices have plunged over 40% in the past six months, oil is still relatively expensive from a long-term historical perspective. As the chart above shows, nominal crude prices today are up 400% from early 1999.
The charts above show the history of nominal and real oil prices since the early 1970s. After adjusting for inflation, oil today is orders of magnitude more expensive than it was in back in 1970 and throughout most of the 1980s and 1990s.
The chart above documents the incredible degree to which the U.S. economy has responded to expensive oil prices. Oil consumption per unit of output across the entire economy has fallen by over 60% since the early 1970s, thanks to more efficient technology and conservation efforts. Oil got very expensive, so we had an incentive to figure out how to use less of it, and we did. Big time. So our demand for oil softened, but only in a good way—we just don't need it so much.
The chart above shows the history of my favorite commodity price index since 1981. Yes, commodity prices are down 20% from their 2011 highs. But they are still up over 130% from their late 2001 lows.
The chart above shows the same commodity index, adjusted for inflation. Here we see that commodities today cost just about as much as they did over 30 years ago,
The chart above shows the inflation-adjusted prices of a broader commodity index (which includes food prices as well as industrial commodity prices). In real terms, commodity prices today are about 7% below their long-term average. Not expensive, but not cheap either.
Copper prices are down 35% from their 2011 highs. Does that make copper cheap? Hardly. Copper is still almost five times more expensive today than it was in 2001. Copper was cheap in the latter half of the 1990s, at a time when the economy was booming—real growth was over 4% a year. In an historical context, copper is still expensive, and that may be one reason why the current recovery has been the weakest on record. Viewed from that perspective, lower copper prices today are like a reduced headwind to growth. Good news.
So all the concerns about falling commodity prices may just be another "wall of worry" that the stock market will sooner or later overcome.