I will be presenting my latest research paper, Causes and Consequences of the Oil Shock of 2007-08, at a conference today at the Brookings Institution. Here I review some results from that paper about what caused oil prices to rise so spectacularly in 2007-08 only to decline even more dramatically afterward.
World real GDP increased by 9.4% between 2003 and 2005. That growth in world income was the primary cause behind an increase in world petroleum consumption of 5 million barrels per day between 2003 and 2005, a 6% increase over the two years. The next two years (2006 and 2007) saw even faster economic growth (10.1% cumulative two-year growth), with Chinese oil consumption alone increasing 870,000 barrels per day. Yet between 2005 and 2007, global oil production stagnated.
What persuaded residents outside of China to reduce petroleum consumption in the face of booming levels of income? The answer is that the price of oil had to increase. How much the price should have risen depends on the price elasticity of demand. Consider the following illustrative calculations. It seems reasonable to maintain that the economic growth in 2006 and 2007 would have resulted in at least as big a shift of the demand curve as resulted from the slightly weaker GDP growth of 2004 and 2005. Adding in the first half of 2008 (when global GDP continued to rise), consider then the consequences of a rightward shift of the demand curve of 5.5 million barrels per day. With production only increasing by 0.5 mb/d over this period, a demand elasticity of ε = 0.06 would imply that the price should have risen from $55/barrel in 2005 to $142/barrel in 2008:H1.
A short-run elasticity of 0.06 for crude petroleum demand could certainly be defended on the basis of estimates in the literature, though so could a higher or lower value. I offer the above calculation simply as an illustration that the observed price behavior could be fully reconciled with reasonable assumptions about supply and demand.
But why then did the price subsequently collapse even more dramatically? A shift of the demand curve back to the left as a result of the impressive global economic downturn is certainly part of the answer. Note, however, that even if global real GDP were to fall by more than 10%– which so far fortunately it has not– that would only put us back to where we were in 2005 (at $55 a barrel), and the price was observed to fall even more than this. We therefore would need to postulate a second factor behind the price decline of 2008:H2, namely, an increase in the price elasticity of demand as consumers had time to make adjustments. Again such a hypothesis is consistent with previous experience, and in particular, between 2007:Q3 and 2008:Q3, U.S. petroleum consumption fell by 8.8%. That drop in U.S. petroleum consumption unambiguously represented the combined effects of lower income and price-induced changes in use.
If we say that one elasticity (0.06) is to be used to account for the 2008:H1 price and another higher elasticity for 2008:H2, there is an implicit claim that market participants were learning imperfectly about the price elasticity of demand. There was a surprisingly long period in which demand responded less than some might have expected to the oil price increases (i.e., consistent with an elasticity of 0.06), and then a very dramatic drop in oil use as a result of the combined influence of falling incomes and changing consumption habits.
My paper also has an extensive examination of an alternative explanation based on a speculative bubble in the price of oil. I will not attempt to reproduce much of that analysis here, but only note the bottom line: in order to reconcile a proposed speculative bubble story with the observed behavior of the physical quantities demanded, supplied, and going into inventories, it is necessary to postulate a very low price elasticity of demand through 2008:H1– precisely the same conditions one would need in order to attribute the price moves entirely to fundamentals.
In terms of policy implications, the paper suggests that sales out of the Strategic Petroleum Reserve could have been explored as a possible tool for curbing excessive speculation, and proposes that the U.S. Federal Reserve needs to take account of possible consequences of its actions for relative prices of commodities. My bottom line was nevertheless the following:
But while the question of the possible contribution of speculators and the Fed is a very interesting one, it should not distract us from the broader fact: some degree of significant oil price appreciation during 2007-08 was an inevitable consequence of booming demand and stagnant production. It is worth emphasizing that this is fundamentally a long-run problem, which has been resolved rather spectacularly for the time being by a collapse in the world economy. However, the economic collapse will hopefully prove to be a short-run cure for the problem of excess energy demand. If growth in the newly industrialized countries resumes at its former pace, it would not be too many more years before we find ourselves back in the kind of calculus that was the driving factor behind the problem in the first place. Policy-makers would be wise to focus on real options for addressing those long-run challenges, rather than blame what happened last year entirely on a market aberration.