Energy vs Climate: A surprising confluence of goals
Guest Commentary by Andrew Dessler
There is an emerging view among some experts that recoverable fossil-fuel reserves are far smaller than previously thought. If so, the Intergovernmental Panel on Climate Change’s (IPCC) highest emissions scenarios could be unrealistically high, thus limiting the worst-case climate change during the 21st century. This view of a constrained fossil-fuel supply points to a potential convergence of thinking about policies and actions needed to address the seemingly divergent problems of energy supply and climate change.
One of the standard techniques for estimating future oil production is the method pioneered by M. King Hubbert. Briefly, Hubbert’s theory involves fitting historical production data to a logistics curve; extrapolation of the curve allows estimation of future production. Hubbert successfully predicted domestic U.S. oil production would peak in the early 1970s, and his theory predicts that world oil production should be peaking about now, which production figures seems to be confirming. Application of Hubbert’s theory to world-oil production suggests that total future recoverable conventional oil is ~1.2 trillion barrels or 7 Zeta Joules (ZJ). Figure 1 shows oil consumption from emissions scenarios produced by the IPCC, along with this estimate based on Hubbert’s method. All IPCC scenarios assume integrated oil production greater than the Hubbert estimate of recoverable oil.
For coal, the canonical wisdom is that there are hundreds of years of availability. However, several recent analyses have cast doubt on this. A recent NRC report on U.S. coal availability concluded, “… there is probably sufficient coal to meet the nation’s needs for more than 100 years at current rates of consumption. However, it is not possible to confirm the often-quoted assertion that there is a sufficient supply of coal for the next 250 years.” Prof. David Rutledge of Caltech has applied a Hubbert-like analysis to coal production data and concluded that the availability of coal is overstimated. The Energy Watch Group, a German think tank, has performed a detailed country-by-country analysis of coal reserves. Integrating their estimate of future coal production, we get 11 ZJ for world coal production from 2008 to 2100 — about one-ninth of the coal reserves cited by the IPCC (Table 4.2 of the fourth assessment report). As is the case for oil, the IPCC’s scenarios’ projected coal consumption generally exceeds this estimate of available resources.
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