Air pollution, deforestation, and widespread burning of coal, oil, and natural gas have increased atmospheric concentrations of carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons.
(Air pollution, deforestation, and widespread burning of coal, oil, and natural gas; have increased; atmospheric concentrations of carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons)
Air pollution, deforestation, and widespread burning of coal, oil, and natural gas
have increased
atmospheric concentrations of carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons