Methane Agricultural wastes 1 Carbon Dioxide 1 Carbon trading 1 Food security 1 Forecasting future climates 1 Fossil fuels 1 Glacial retreat 1 Greenhouse effect 1 Health threats, Climate change 1 Inorganic chemistry 1 Nitrogen 1 Past climates 1 Polar changes 1 Sea level rising 1 Warning signs, Climate change 1