Winter 2013

A Trillion Tons

Hal Harvey, Franklin M. Orr, Jr., and Clara Vondrich

There is a consensus among scientists that stark dangers await in a world where the global mean temperature rises by more than about 2 degrees Celsius. That threshold corresponds to a collective human carbon emissions “budget” of around a trillion tons, of which half has been spent. This paper uses a new simulation model to look at strategies to stay within that budget, specifically assessing the impact of improvements in energy efficiency, aggressive deployment of renewables, and energy technology innovation. The simulations examine the timing of investments, turnover of capital stock, and the effect of learning on costs, among other factors. The results indicate that efficiency, renewables, and technology innovation are all required to keep humanity within the trillion-ton budget. Even so, these measures are not by themselves sufficient: changes in land use and a price on carbon emissions are also needed.

HAL HARVEY is CEO of Energy Innovation: Policy and Technology LLC and Senior Fellow for Energy and the Environment at the Paulson Institute at the University of Chicago. He is the founder of the ClimateWorks Foundation, where he previously served as CEO. He is former Environment Program Director at The William and Flora Hewlett Foundation and founder and past President of the Energy Foundation. An energy engineer, he has worked on energy policy in a dozen countries.

FRANKLIN M. ORR, JR., is the Keleen and Carlton Beal Professor in the Department of Energy Resources Engineering and Director of the Precourt Institute for Energy at Stanford University. He is also a Senior Fellow at the Woods Institute for the Environment. His research focuses on understanding the physical mechanisms that control displacement performance in gas injection processes for oil recovery and storage of greenhouse gases. His work has appeared in the Journal of Fluid MechanicsEnergy Conversion and Management, and the International Journal of Greenhouse Gas Control, among other publications.

CLARA VONDRICH is Director of Leadership Initiatives at the ClimateWorks Foundation. She is an attorney with a background in international arbitration and energy policy. Previously, she served as Counsel to the President's Commission on the BP Deepwater Horizon Oil Spill, focusing on ecological restoration and environmental justice. She also helped prepare amicus briefs in support of state plaintiffs in the landmark U.S. Supreme Court case American Electric Power v. Connecticut, which sought to hold major electric utilities liable for their contribution to climate change.

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