Related by context. Frequent words. (Click for all words.) 60 climate change 60 reducing greenhouse gas 57 global warming 55 reduce carbon emissions 55 greenhouse gas emissions 53 carbon emissions 53 greenhouse gases 53 greenhouse emissions 51 greenhouse gas 50 emission reduction 49 carbon dioxide emissions 49 reduce greenhouse gas 48 emissions 48 renewable energy 46 fossil fuels 45 renewable energies 45 carbon capture 44 renewables 44 CO2 emissions 44 alternative fuels 44 environmental sustainability 43 Climate Change 43 biofuels 42 GHG emissions 42 renewable fuels 42 environmentalism 41 greening 41 Global warming 41 nuclear disarmament 41 Climate Action 41 environmental stewardship 41 polluters 40 carbon 40 environmentally sustainable 40 burning fossil fuels 40 environmentally friendly 39 emission 39 sustainable 39 conserving 39 Kyoto Protocol 39 greener 39 deforestation 39 fossil fuel 39 zero emission 39 environmentally 39 Emissions 39 sustainability 38 Secretary Steven Chu 38 poorer nations 38 emitters 38 Climate 38 environmentally sound 37 offshore wind 37 Kyoto 37 conservation 37 Environmentalists 37 energy 37 Sustainability 37 emerging economies 37 environmental 37 climate 37 childhood obesity 36 renewable 36 combatting 36 environmentalists 36 biodiversity 36 denuclearization 36 environmentally conscious 36 carbon dioxide 36 UNEP 36 pollution 35 House Speaker Nancy 35 bioenergy 35 Clean Energy 35 reforming 35 Sen. Barbara Boxer 35 planting trees 35 Renewable 35 Sustainable 35 carbon footprint 35 biofuel 35 smart grid 34 eco friendly 34 environmentally responsible 34 hydrogen fuel 34 nonproliferation 34 President Barack Obama 34 ecologically 34 CO2 34 developing 34 disarmament 34 carbon neutral 34 environmental degradation 34 Sustainable Development 34 Environmental Protection Agency 33 Earth Hour 33 curbing 33 air pollution 33 combating terrorism 33 EPA 33 combating