An international agreement initiated by the United Nations, the Kyoto Protocol is a document that aims to reduce global emissions worldwide in an effort to stem and eventually reverse global warming. Adopted on December 11, 1997, the agreement has been signed by representatives from 184 nations. A central aspect of the Kyoto Protocol is establishing scheduled reductions in emissions, reducing greenhouse gases relative to 1990 levels by five percent over the course of the years 2008 through 2012. Countries participating in the agreement can earn emissions-reducing credits by either reducing pollutants produced in their own countries, or through a “carbon market,” which is a system of emissions trading. In other words, a country that wishes to allow more emissions within their borders can purchase emissions credits from countries with lower levels and still be in compliance with the treaty. Countries can also earn credits by sponsoring emissions-reducing programs in foreign nations or building clean factories and power plants in other countries.