“Equitable” Climate Change Mitigation: A New Formulation Robert Socolow Princeton University Informal Thematic Debate of the UN General Assembly on Climate Change as a Global Challenge Panel on Mitigation Strategies in the context of Sustainable Development United Nations July 31, 2007 For further reading, see two papers by Steve Pacala and Rob Socolow: 1)“Stabilization Wedges: Solving the climate problem for the next 50 years with current technologies,” Science, 305 (5686), August 13, 2004, (and its Supporting Online Material). 2)“A plan to keep carbon in check,” Scientific American, September 2006,

Billion of Tons of Carbon Emitted per Year Currently projected path Flat path Historical emissions 2.0  GtC/y Seven “wedges” Wedges O Today and in 50 years, global per-capita emissions are ≈ 1 tC/yr. Goal: In 50 years, same global emissions as today

Energy Efficiency Decarbonized Electricity Fuel Displacement by Low-Carbon Electricity Forests & Soils Decarbonized Fuels Stabilization Triangle GtC/y 14 GtC/y Fill the Stabilization Triangle with Seven Wedges Methane Management

OECD and non-OECD shares SourceI Socolow and Pacala, Scientific American, September 2006, p.56

Per-capita Carbon Emissions Source: M. Tavoni and S. Chakravarty, 7-07 Bins III-V in 2030: 9 of 11 Gt/yr emissions OECD 45% 3 of 8 billion people OECD 40% Equitable policy: Free pass in 2030 for the 5 billion people in Bins I and II

Can We Do It? People (we!) are becoming increasingly determined to lower the risk that we and our children will experience major social dislocation and environmental havoc as a result of rising CO 2 in the atmosphere …and we are learning that there are many ways of changing how we live, what we buy, and how we spend our time, that will make a difference. We are in the midst of a discontinuity: What once seemed too hard has become what simply must be done. Precedents include abolishing child labor, addressing the needs of the disabled, and mitigating air pollution.