Wedges

Sustainable Carbon Emissions

Need multiple options that reduce emissions by 1 GT/year for 50 years.

S. Pacala and R. Socolow, Science, 305, 13 Aug. 2004, p. 968-972 or National Geographic (2007) or Azimuth Project (2013)

Efficiency: Double fuel efficiency of 2 billion cars (30 mpg to 60 mpg) or cut car miles in half

Wind power: Increase wind capacity by 10 times (2 million 1-MW wind turbines)

Solar energy: Increase solar capacity by 100 times (20,000 km²)

Natural gas: Replace 1,400 coal plants with CH₄

Nuclear energy: Triple global nuclear capacity

Biofuels: Increase ethanol production 12 times (1/6 world cropland or the size of India)

Coal: Capture and sequester CO₂ from 800 coal plants

But we waited too long so now we need 2 more wedges to stabilize

R. Socolow, Bulletin of the Atomic Scientists, 27 September 2011

At current burn rates we’ll double CO₂ from preindustrial levels by 2050, and quadruple it by the end of this century. We’ve got enough fossil fuels to send it to seven times its preindustrial levels. (Azimuth Project)

The safe level may be only 350 ppm (350.org)