Related by context. Frequent words. (Click for all words.) 43 reducing carbon emissions 43 Concerned Scientists 43 reducing CO2 emissions 42 CO2 emission 42 carbon dioxide emission 41 greenhouse gas emission 41 alternative fuels 41 reduce greenhouse gas 41 reduce carbon emissions 41 greenhouse gas emissions 40 emissions 40 zero emission 40 Fuel Efficiency 40 David Doniger 40 greenhouse emissions 40 carbon dioxide emissions 39 greenhouse gas 39 reducing greenhouse gas 38 emission reductions 38 CO2 emissions 38 CAFE standards 38 curbing greenhouse gases 38 carbon emissions 38 emission reduction 38 tailpipe emissions 38 heat trapping emissions 37 greenhouse gases 37 Alden Meyer 37 climate change 37 cleaner fuels 37 C# emissions 37 greenhouse gas GHG emissions 37 global warming 37 Fuel Economy 37 greenhouse gas GHG 37 Carbon dioxide emissions 37 carbon emission 37 hydrogen powered 36 GHGs 36 Energy Efficient Economy 36 carbon dioxide CO2 emissions 36 PHEV 36 ACEEE 36 heat trapping carbon dioxide 36 emission 35 Copenhagen Climate 35 Emissions 35 GHG emissions 35 exhaust emissions 35 curbing greenhouse gas 35 gas guzzling cars 35 hydrogen fuel 35 greenhouse gasses 34 PHEVs 34 pollutant emissions 34 biofuels 34 UCS 34 Greenhouse Gas 34 mpg 34 Sunita Narain 34 Alternative Fuels 34 flex fuel 34 hybrid electric 34 Pembina Institute 34 carbon emitting 34 Greenhouse Gas Emissions 33 Carlgren 33 gas guzzling 33 Worldwatch Institute 33 Climate Change 33 Jeff Tittel 33 fossil fuel 33 fossil fuels 33 speed limiters 33 carbon dioxide emitted 33 renewable fuels 33 emission norms 33 Kim Carstensen 33 achievable 33 USCAP 33 diesel 32 greener 32 Climate 32 carbon emitted 32 hybrid 32 PlaNYC 32 GHG 32 Sustainability 32 Kyoto Protocol expires 32 Alternative Fuel 32 Greener 32 gas guzzling vehicles 32 regulate greenhouse gases 32 Low Carbon 32 regulating greenhouse gases 32 greenhouse gases emitted 32 Clean Air 32 Hydrogen 31 Natural Resources Defense 31 Sierra Club 31 emit carbon dioxide