Related by context. Frequent words. (Click for all words.) 88 CO2 81 greenhouse gases 78 carbon dioxide emissions 76 greenhouse gas 71 methane 71 carbon emissions 70 sulfur dioxide 69 greenhouse gas emissions 69 CO2 emissions 68 emissions 65 gases 65 carbon 64 heat trapping gases 64 greenhouse emissions 64 pollutants 63 nitrogen 63 water vapor 62 GHG emissions 61 GHG 61 nitrogen oxides 61 carbon emission 59 pollutant 59 reduce carbon emissions 57 burning fossil fuels 57 emission 57 Emissions 57 mercury emissions 57 hydrogen 56 fossil fuels 56 emission reductions 56 pollution 56 fossil fuel 55 reducing carbon emissions 54 Methane 54 ozone 53 carbon sequestration 52 particulate matter 52 methane gas 52 emission reduction 52 air pollution 51 aerosols 51 ammonia 51 biomass 51 carbon capture 51 particulates 51 acid rain 49 global warming 49 mercury 48 toxic chemicals 48 hydrogen sulfide 48 volatile organic compounds 48 biofuel 47 oxygen 47 combustion 47 helium 47 CO 47 emitted 47 coal fired 47 carbon footprint 47 vapor 47 nitrous oxide 47 sulfur 47 polluting 46 carbon monoxide 46 emitters 46 polluters 46 ozone layer 46 hydrocarbons 46 sediment 46 biofuels 46 soot 46 climate change 45 coal 45 photosynthesis 45 polluter 45 permafrost 45 phosphorus 45 groundwater 45 carbon credits 44 oceans 44 atmospheric 44 nutrient 44 toxins 44 compressed air 44 gaseous 44 carbon offsets 43 sulfuric acid 43 nitrate 43 emit 43 sugars 43 methanol 43 manure 43 hydrogen fuel 43 chlorine 42 hazardous chemicals 42 contaminants 42 landfills 42 reduce greenhouse gas 42 radioactive material 42 biogas 42 Hydrogen