After detailed reviews, the Intergovernmental Panel on Climate Change (IPCC) concluded that "the balance of evidence suggests a discernible human influence on global climate." (UNEP, 1992) Three "greenhouse" gases are of greatest concern: carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Overall about 80% of greenhouse gas (GHG) emissions from human activities are related to the production and use of energy and fossil fuel use in particular. Most of the remaining 20% is associated with agriculture and changes in land use.

Urban air quality management can play a significant role in reducing GHG emissions, through more efficient energy use, and the application of other strategies that reduce both local and global emissions.