Reducing greenhouse gas emissions requires a variety of strategies. Pacala and Socolow (2004) present a variety of “wedges” that would jointly cause CO2 emissions to level off within the next few decades. These wedges include developing forms of renewable energy such as wind or solar, capturing CO2 at power plants before it is released, improving fuel and energy efficiency, and altering patterns of land-use. On a global scale, the United Nations Framework Convention on Climate Change (UNFCCC) meets regularly to discuss climate change mitigation and adaptation. In 1997, most of the nations signed a pact called the Kyoto Protocol, but it expires in 2012, and the UNFCCC has yet to produce a follow-up treaty.
Image source: Norm Christensen (adapted from Pacala and Socolow 2004)