Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technology Robert Socolow Princeton University Princeton, NJ, USA In-Session Workshop on Mitigation SBSTA 21 December 9, 2004 Buenos Aires This talk is based on a paper of the same title, by Stephen Pacala and Robert Socolow, published in the August 13, 2004, issue of Science, 305 (5686), pp , and its Supporting Online Material.

Billion of Tons of Carbon Emitted per Year Historical emissions Past Emissions

Billion of Tons of Carbon Emitted per Year Historical emissions Stabilization Triangle Currently projected path Flat path The Stabilization Triangle O Interim Goal

Billion of Tons of Carbon Emitted per Year Stabilization Triangle Currently projected path Flat path Historical emissions Easier CO 2 target ~850 ppm Tougher CO 2 target ~500 ppm Targets O

The Interim Goal and the Stabilization Triangle The Interim Goal: The Same Emissions in 2054 as Today The interim goal is on the path to stabilization below doubling ( ppm) emissions are projected to be twice those of today, if carbon emissions are ignored.

The Interim Goal is Within Reach Reasons for optimism: The world today has a terribly inefficient energy system. Carbon emissions have zero economic cost. Most physical plant has a lifetime of less than 50 years.

Billion of Tons of Carbon Emitted per Year Currently projected path Flat path Historical emissions GtC/y 7 GtC/y Seven wedges Wedges O

What is a Wedge? A wedge is an activity reducing the rate of carbon build-up in the atmosphere that grows in 50 years from zero to 1.0 Gt(C)/yr. 1 GtC/yr 50 years Total = 25 Gigatons carbon

Energy Efficiency & Conservation Fuel Switch Forests & Soils CO 2 Capture and Storage Nuclear Fission Stabilization Triangle GtC/y 14 GtC/y Fill the Stabilization Triangle with Seven Wedges Renewable Electricity and Fuels

Humanity Already has the Tools READINESS: All wedge technologies are already deployed somewhere at commercial scale. PORTFOLIO: No single wedge technology can do the whole job, or even half the job. CHOICE: Not every wedge technology is needed.

Efficiency and Conservation transportbuildings industry power lifestyle Effort needed by 2054 for 1 wedge: 2 billion cars at 60 mpg instead of 30 mpg.

Wind Electricity Effort needed by 2054 for 1 wedge: Two million 1 MW windmills. Today: 40,000 (2%) Prototype of 80 m tall Nordex 2,5 MW wind turbine located in Grevenbroich, Germany (Danish Wind Industry Association)

Power with Carbon Capture and Storage Graphics courtesy of DOE Office of Fossil Energy Effort needed by 2054 for 1 wedge: Carbon capture and storage at 800 GW coal power plants.

Carbon Storage Effort needed by 2054 for 1 wedge: 3500 Sleipners A flow of CO 2 into the Earth equal to the flow of oil out of the Earth today Graphic courtesy of Statoil ASA Start now to gain experience with the permitting of storage sites.

Biofuels Effort needed by 2054 for 1 wedge: Two billion 60 mpg cars running on biofuels 250 million hectares of high-yield crops (one sixth of world cropland). Usina Santa Elisa mill in Sertaozinho, Brazil (

Effort needed by 2054 for 1 wedge: Eliminate tropical deforestation and Rehabilitate 400 million hectares (Mha) temperate or 300 Mha tropical forest Natural Stocks Photo: SUNY Stonybrook Effort needed by 2054 for 1 wedge: Conservation tillage on all cropland.. Forests Soils Photo: Brazil: Planting with a jab planter. FAO

Other Wedges ELECTRICITY Natural gas for coal Nuclear power Power from photovoltaics (PV) FUELS Synthetic fuel from coal, natural gas, and biofuels, with carbon capture and storage Hydrogen from coal and natural gas, with carbon capture and storage Hydrogen from nuclear energy Hydrogen from wind or PV METHANE MANAGEMENT landfill gas, cattle, rice, natural gas

Consensus Building at COP-10 Advocates of particular wedges agree: 1. The best wedges for one country may not be the best for another. 2. It is too soon to pick winners. 3. The environmental and social costs of scale-up need attention. 4. Subsidy of early stages is often desirable. 5. At later stages, markets help to choose the best wedges. Can a consensus in favor of early action be built on stabilization wedges?