Related by context. Frequent words. (Click for all words.) 72 atmospheric carbon dioxide 59 greenhouse gases 59 extinctions 58 greenhouse gasses 54 global warming 54 heat trapping gases 53 carbon dioxide 52 climate change 52 atmospheric 52 greenhouse gas emissions 52 ocean acidification 52 greenhouse emissions 50 carbon dioxide emissions 50 CO2 50 polar regions 49 mass extinction 49 carbon dioxide CO2 49 oceans 49 ozone 48 Greenland ice 48 latitudes 48 deforestation 47 WMO 47 Global warming 47 emissions 47 burning fossil fuels 47 IPCC 47 Climate Change IPCC 47 GHG emissions 47 water vapor 46 greenhouse gas 46 melting glaciers 46 carbon emissions 46 volcanic activity 46 polar ice 46 glaciers 46 CO2 emissions 46 global warming gases 45 temperatures 45 emission reductions 45 permafrost 45 climate 45 sunspots 45 mercury emissions 45 ozone layer 45 salinity 45 crop yields 45 climatologists 45 biodiversity 44 degree Fahrenheit 44 Montreal Protocol 44 cosmic rays 44 sulfur dioxide emissions 44 Carbon dioxide 44 biosphere 44 Antarctic ice 44 Climate Change 44 La Nina 44 aerosols 43 Emissions 43 methane 43 warming 43 degree Celsius 43 gases 43 World Meteorological Organization 42 degrees Fahrenheit 42 reducing carbon emissions 42 planetary 42 mercury pollution 42 pollutant 42 Earth 42 greenhouse gas emission 42 fossil fuels 42 pollutants 42 Global Warming 42 degrees Celsius 42 volcanic eruptions 41 ppm 41 Arctic Ocean 41 El Nino 41 acid rain 41 planet 41 precipitation 41 climatic 41 GHG 41 emission 41 La Niña 41 daytime temperatures 41 natural catastrophes 41 tropical forests 41 geoengineering 41 Deforestation 40 carbon emission 40 oscillations 40 Climate 40 ecosystems 40 Antarctica 40 droughts 40 Copenhagen Accord 40 air pollution 40 tropics