Hansen: Implications of ”peak oil” for atmospheric CO2 and climate

Peaking of global oil production may have a large effect on future atmospheric CO2 amount and climate change, depending upon choices made for subsequent energy sources. We suggest that, if estimates of oil and gas reserves by the Energy Information Administration are realistic, it is feasible to keep atmospheric CO2 from exceeding approximately 450 ppm, provided that future exploitation of the huge reservoirs of coal and unconventional fossil fuels incorporates carbon capture and sequestration. Existing coal-fired power plants, without sequestration, must be phased out before mid-century to achieve this limit on atmospheric CO2. We also suggest that it is important to “stretch” oil reserves via energy efficiency, thus avoiding the need to extract liquid fuels from coal or unconventional fossil fuels. We argue that a rising price on carbon emissions is probably needed to keep CO2 beneath the 450 ppm ceiling.

Introduction

M. King Hubbert, the late petroleum geologist and Shell oil company consultant, articulated
the notion that oil production would peak when about half of the economically recoverable
resource had been exploited. His successful prediction of peak oil production in the continental
United States (Hubbert, 1956) has encouraged numerous analysts to subsequently apply his
model or variations thereof to global oil production. The concept of peak extraction of a finite
nonrenewable resource constrained by geology and geography has received support from similar
patterns of growth, peak production, and decline of mineral resources (van der Veen, 2006),
natural gas (Lam, 1988), and coal (Milici and Campbell, 1997) in specific regions.

There is intense disagreement about when global peak oil might occur, but it is widely
accepted that peak oil will occur at some point this century (Wood et al., 2003; Kerr, 2005).
Despite the obvious relevance of