The UN Framework Convention in Climate Change aims to limit climate change by reducing carbon dioxide emissions and removing carbon dioxide through its absorption by forests and soils. A policy to promote this goal has been favorable treatment of renewable energy to replace fossil fuels. But there are important differences in achieving this goal across various renewable energy sources. Almost half of the renewable energy consumed in the United States comes from biomass (plant material) that releases heat and carbon dioxide when burned. While energy derived from burning trees and other plants may be slowly renewable through regrowth, the use of forest biomass releases high carbon dioxide emissions and other air pollutants, unlike wind and solar that are instantly renewable, resources that emit no carbon dioxide while producing electricity.