Related by context. Frequent words. (Click for all words.) 74 greenhouse gases 72 carbon dioxide 68 heat trapping gases 67 greenhouse gas 66 carbon dioxide CO2 66 greenhouse gasses 65 carbon dioxide emissions 64 global warming gases 64 greenhouse gas emissions 61 CO2 60 greenhouse emissions 60 carbon emissions 59 emissions 58 GHGs 58 methane 57 greenhouse gas emission 56 burning fossil fuels 55 CO2 emissions 54 nitrogen oxides 54 nitrogen oxide 54 atmospheric carbon dioxide 53 Carbon dioxide 53 carbon dioxide CO2 emissions 52 carbon emission 52 pollutants 52 GHG emissions 52 gases 51 fossil fuel 51 sulfur dioxide 51 emission 51 Emissions 51 fossil fuels 50 mercury emissions 50 pollution 50 CO2 emission 50 reduce carbon emissions 50 water vapor 50 emission reductions 50 GHG 49 carbon 49 global warming 48 mercury pollution 48 nitrogen oxide emissions 48 emission reduction 47 reducing carbon emissions 47 gases blamed 47 tailpipe emissions 47 nitrogen 46 air pollution 46 sulfur dioxide emissions 46 pollutant 45 ozone pollution 45 methane gas 45 climate change 45 oceans 45 acid rain 45 Methane 44 groundwater 44 particulates 43 reduce greenhouse gas 43 ozone 43 particulate matter 43 deforestation 43 Kyoto Protocol 43 polluters 43 soot 43 polluting 43 gasses 43 HFCs 42 smog 42 freshwater 42 snowmelt 42 exhaust emissions 41 emitters 41 NOx 41 mercury 41 renewable fuels 41 toxic chemicals 41 aerosols 41 renewable 41 emission allowances 41 renewable energy 41 reducing CO2 emissions 40 gigawatt hours 40 Kyoto accord 40 gigawatts 40 melting glaciers 40 aquifers 40 regulate carbon dioxide 40 Montreal Protocol 40 biofuels 40 exhaust fumes 40 VOCs 40 polluter 40 biomass 40 Kyoto pact 39 atmospheric 39 biofuel 39 carbon credits 39 CFCs 39 manure