Plains CO2 Reduction (PCOR) Partnership

CO2 Wedges – Cutting Human CO2 Emissions Down to Size

Human (also known as anthropogenic) CO2 emissions result from human activities like burning fossil fuel for energy, making cement from limestone, or plowing land for farming. The level of human CO2 emissions to the atmosphere is rising, and the CO2 concentration in the atmosphere is rising.

Significant fossil fuel use began in the 1850s with the growth of steelmaking and railroads. The fossil fuel portion of human global CO2 emissions since the 1750s is shown in the figure below.


World CO2 emissions are projected to rise from 29.0 billion metric tons in 2006 to 33.1 billion metric tons in 2015 and then grow to 40.4 billion metric tons in 2030—an increase of 39% over the projection period. By midcentury, CO2 emissions are expected to be twice what they are today. Most of the growth in these human CO2 emissions will come from the rapidly developing economies of China and India.


Many scientists believe that if we can prevent 200 billion tons of human CO2 from entering the atmosphere over the next 50 years, we can stabilize the amount of CO2 in the atmosphere at the 500-ppm level, which may greatly reduce the threat of climate change.2

The CO2 wedge concept suggests ways in which we can apply today’s technology to reduce carbon emission in large amounts known as wedges. Each carbon reduction wedge would be designed to prevent 1 billion tons of carbon from entering the atmosphere by 2050. If we start applying theses actions to create just eight wedges, we could prevent 200 billion tons of CO2 from entering the atmosphere by midcentury.3

Both terrestrial and geologic sequestration (as part of Carbon Capture and Storage) play a key role in the CO2 wedge concept.2

Learn more at the Princeton University Carbon Mitigation Initiative Web site.4

  1. OECD stands for the Organization for Economic Cooperation and Development and consists of the world’s industrialized democracies, including the United States, the countries of the European Union, Australia, and Japan. The bulk of the projected economic growth and growth in anthropogenic CO2 emissions is in the non-OECD countries of China and India.
  2. CO2 levels equal to 0.06% of the atmosphere (six parts in 10,000 parts) and preindustrial levels of CO2 in the atmosphere are estimated to have been 0.03% (three parts in 10,000 parts).
  3. Pacala, S., and Sokolow, R., 2004, Stabilization wedges – solving the climate problem for the next 50 years with current technologies: Science, v. 305, p. 968–972.
  4. Princeton University’s Carbon Mitigation Initiative, (accessed on January 14, 2010).