Related by context. Frequent words. (Click for all words.) 68 carbon dioxide emissions 65 CO2 emissions 65 Emissions 63 greenhouse gas emissions 63 greenhouse gases 63 emissions 62 carbon dioxide CO2 emissions 61 greenhouse emissions 61 carbon dioxide CO2 61 carbon emissions 61 Carbon dioxide 61 carbon dioxide 60 greenhouse gasses 60 GHGs 59 CO2 58 nitrogen oxide emissions 57 burning fossil fuels 57 carbon dioxide emission 56 GHG emissions 56 greenhouse gas 56 nitrogen oxide 55 CO2 emission 55 sulfur dioxide emissions 55 exhaust emissions 55 pollutants 54 mercury emissions 54 greenhouse gas GHG emissions 54 reduce carbon emissions 53 atmospheric carbon dioxide 53 particulate matter 53 air pollution 52 greenhouse gas emission 52 emission reductions 52 global warming gases 52 heat trapping gases 52 pollutant 52 nitrogen oxides 52 atmospheric CO2 52 fossil fuels 51 reducing CO2 emissions 51 carbon emission 51 reducing carbon emissions 51 emission 50 pollution 49 tailpipe emissions 49 NOx 49 mercury pollution 49 sulfur dioxide 48 global warming 47 fossil fuel 47 Global warming 47 particulates 46 emission reduction 46 absorb carbon dioxide 46 heat trapping greenhouse gases 46 gases 45 regulate greenhouse gases 44 ozone pollution 44 biofuels 44 methane 44 nitrogen dioxide 43 SO2 43 ozone depletion 43 Emission 43 VOCs 43 anthropogenic 43 ozone 43 polluting 43 biofuel 43 GHG 43 cleaner fuels 43 combustion 43 climate change 43 internal combustion engines 42 combustion engine 42 acid rain 42 soot 42 mercury 42 emitted 42 Carbon monoxide 42 regulate carbon dioxide 42 internal combustion 42 diesel engines 42 Renewable energy 42 biomass 42 polluter 42 Pollution 42 Deforestation 42 carbon 41 gasses 41 CFCs 41 TWh 41 diesel exhaust 41 polluters 41 coal fired 41 renewables 41 Methane 41 particle pollution 40 smog 40 Temperatures 40 Plastic bags