Related by context. Frequent words. (Click for all words.) 68 ozone layer 62 protective ozone layer 56 Ozone Layer 54 ozone 52 ozone depletion 50 chlorofluorocarbons 49 marine ecosystems 48 ecosystems 48 biosphere 47 ozone depleting substances 47 ocean ecosystems 47 coastal ecosystems 47 carbon sinks 47 CFCs 47 atmospheric circulation 46 atmospheric carbon dioxide 46 marine ecosystem 46 Sulfur dioxide 46 polar regions 46 acidification 46 coral reefs 45 polar caps 45 atmospheric CO2 45 peatlands 45 Montreal Protocol 45 chlorofluorocarbons CFCs 45 aquatic ecosystems 45 coral bleaching 45 absorb carbon dioxide 44 acid rain 44 tropical rainforests 44 coastal wetlands 44 volcanic eruptions 44 melting permafrost 44 carbon dioxide 43 magnetosphere 43 aerosols 43 forest ecosystems 43 tropical forests 43 greenhouse warming 43 biodiversity 43 carbon dioxide CO2 43 reefs 43 wildlife habitats 43 cosmic rays 43 species extinctions 42 mid latitudes 42 peat bogs 42 boreal forests 42 phytoplankton 42 oceans 42 biota 42 greenhouse gas concentrations 42 CO2 concentrations 41 sulfur dioxide 41 crustal 41 peatland 41 albedo 41 mountain glaciers 41 airborne pollutants 41 permafrost 41 corals 41 refrigerants 41 wetland habitats 41 freshwater wetlands 41 greenhouse gases 41 marine biodiversity 41 Martian atmosphere 40 habitats 40 atmospheric chemistry 40 UV radiation 40 reactive oxygen species 40 anthropogenic 40 boreal forest 40 World Meteorological Organisation 40 Greenhouse gases 40 meltwater 40 atmospheric 40 UV rays 40 solar flares 40 biodiversity hotspots 40 ultraviolet rays 40 vegetation 40 insect infestations 40 coral 40 ozone concentrations 40 cosmic radiation 40 soot particles 40 Carbon Dioxide 40 seamounts 40 pollutants 40 microorganism 40 heat trapping gases 40 Carbon dioxide 40 wetlands 40 oxidants 39 Earth 39 burning fossil fuels 39 greenhouse gases emitted 39 coral reef 39 World Meteorological Organization