Related by context. Frequent words. (Click for all words.) 69 fossil fuels 62 fossil fuel 55 burning fossil fuels 52 Renewable energy 51 greenhouse gases 50 finite resource 50 greenhouse gasses 49 Carbon dioxide 48 liquid fuels 47 renewables 47 renewable 47 Global warming 46 biofuels 46 carbon dioxide 46 atmospheric carbon dioxide 46 Plastic bags 46 renewable energies 46 internal combustion engines 45 greenhouse emissions 45 coal 45 heat trapping gases 45 CO2 45 GHGs 45 feedstock 44 alternative fuels 44 bio fuels 44 carbon dioxide emissions 44 greenhouse gas 44 renewable energy 44 internal combustion engine 44 feedstocks 44 greenhouse gas emissions 44 alternative energies 44 Lithium ion batteries 44 biomass 43 gases 43 CFCs 43 carbon dioxide CO2 43 Wind turbines 43 carbon emissions 43 hydrocarbons 43 arable land 43 methane 43 reducing carbon emissions 42 rare earths 42 CO2 emissions 42 carbon sinks 42 Microbes 42 Natural gas 42 energy 42 combustion engines 41 atmospheric CO2 41 global warming 41 fuels 41 hydroelectricity 41 refrigerants 41 heat trapping greenhouse gases 41 natural gas 41 minerals 41 Methane 40 combustion engine 40 Prescription drugs 40 electricity 40 hydrogen 40 baseload 40 internal combustion 40 renewable fuels 40 emissions 40 reducing CO2 emissions 40 emission reductions 40 Smartphones 39 biofuel 39 cleaner fuels 39 polluting 39 raw materials 39 tar sands 39 GHG emissions 39 desalinated water 39 diesels 39 chemical fertilizers 39 biosphere 39 Bottled water 39 fossil 39 Human beings 39 photovoltaics 39 Hybrids 39 vast quantities 39 aquifers 39 EVs 38 Iron ore 38 vegetable oils 38 bioethanol 38 Renewables 38 climate change 38 PGMs 38 Solar panels 38 gas guzzling SUVs 38 freshwater 38 oceans 38 carbon sequestration 38 anthropogenic