Related by context. Frequent words. (Click for all words.) 73 greenhouse gases 72 carbon dioxide emissions 70 greenhouse gas emissions 66 carbon emissions 65 emissions 65 carbon dioxide 65 CO2 emissions 65 GHG emissions 64 greenhouse emissions 64 greenhouse gas 63 heat trapping gases 60 greenhouse gas emission 59 CO2 59 reduce carbon emissions 59 carbon emission 59 carbon dioxide CO2 56 burning fossil fuels 56 GHG 55 emission 53 emission reductions 52 carbon footprint 52 reducing carbon emissions 51 mercury emissions 51 pollution 50 emission reduction 50 global warming 50 Emissions 50 tailpipe emissions 50 pollutants 49 methane 49 fossil fuels 48 nitrogen oxides 48 carbon 48 air pollution 47 nitrogen oxide 47 fossil fuel 46 Carbon dioxide 46 gases 46 carbon footprints 45 reduce greenhouse gas 45 pollutant 45 emitted 44 polluting 44 climate change 44 sulfur dioxide 44 ozone 43 volatile organic compounds 43 biofuels 43 carbon offsets 43 emitters 42 carbon neutral 42 deforestation 42 emit 41 toxic chemicals 41 alternative fuels 41 polluters 41 particulate matter 41 VOCs 41 environmental impacts 41 biofuel 40 environmentally sound 40 carcinogens 40 carbon sequestration 40 aerosols 40 environmentally friendly 40 carbon credits 40 particulates 40 renewable fuels 40 acid rain 40 zero emission 39 pollute 39 biomass 39 polluter 39 emitting 39 NOx 38 methane gas 38 gasses 38 Kyoto Protocol 38 ozone layer 38 renewable energy 37 bio fuels 37 hazardous chemicals 37 soot 37 toxic substances 37 harmful chemicals 37 environmentally sustainable 37 environmentalists 37 Clean Air 36 water vapor 36 composting 36 mercury 36 diesel powered 36 emits 36 cleaner burning 36 Deforestation 36 environmental 36 greening 36 EPA 36 renewable 36 smog 35 organics