Related by context. Frequent words. (Click for all words.) 64 fossil fuel 64 carbon emission 62 carbon emissions 62 fossil fuels 61 greenhouse gas emissions 61 emissions 60 carbon dioxide emissions 60 polluting 59 greenhouse gases 59 emission 58 CO2 emissions 57 greenhouse emissions 57 carbon 56 reduce carbon emissions 56 greenhouse gas 56 emission reduction 55 renewables 55 emission reductions 55 GHG emissions 55 renewable energy 53 Emissions 53 renewable 52 CO2 52 biofuels 51 biofuel 51 bio fuels 51 gas guzzling 50 polluters 50 alternative fuels 49 zero emission 49 coal fired 49 burning fossil fuels 49 carbon dioxide 49 polluter 49 renewable energies 49 renewable fuels 48 emitters 47 emitting 47 internal combustion engine 46 environmentally friendly 46 biomass 46 ethanol 45 carbon footprints 45 coal 45 carbon neutral 45 energy 44 diesel 44 pollution 44 Renewable energy 44 hydrogen powered 43 carbon footprint 43 cleaner burning 43 diesel powered 43 climate change 43 carbon offsets 43 biodiesel 43 bio diesel 43 environmentally sound 43 carbon credits 42 pollute 42 carbon capture 42 environmentally sustainable 42 gas guzzlers 42 EVs 42 Kyoto Protocol 42 tar sands 42 hydrogen 41 hydrogen fuel 41 reducing greenhouse gas 40 Climate Change 40 cellulosic ethanol 40 global warming 40 emit 40 combustion 40 greener 40 industrialized 40 reduce greenhouse gas 40 mercury emissions 40 Kyoto protocol 40 diesels 39 fuels 39 eco friendly 39 Climate Action 39 automobiles 39 air pollution 39 Ethanol 38 fuel 38 hybrid electric 38 Hydrogen 38 pollutant 38 greenest 38 Renewables 37 environmentally 37 flex fuel 37 feedstocks 37 multinational corporations 37 electric 37 diesel engines 37 bioenergy 37 eco 36 cogeneration