Related by context. Frequent words. (Click for all words.) 64 greenhouse warming 62 mass extinctions 60 sunspot activity 59 glaciation 59 Little Ice Age 58 atmospheric concentrations 57 Medieval Warm Period 57 CO2 concentrations 57 extinctions 56 volcanism 56 atmospheric CO2 55 ozone depletion 54 atmospheric carbon dioxide 54 anthropogenic 53 mountain glaciers 53 greenhouse gas concentrations 53 polar caps 53 mid latitudes 53 plate tectonics 53 atmospheric circulation 53 volcanic eruptions 52 climatological 51 glaciers 51 mass extinction 51 heatwaves 50 Droughts 50 Serreze 50 climatologists 50 megafauna 50 decadal 50 temperate regions 49 ENSO 49 polar regions 49 epochs 49 Holocene 49 NSIDC 49 phenomena 49 influenza pandemics 49 sunspots 49 upwelling 48 global warming 48 volcanic activity 48 mammoths 48 landmasses 48 carbon dioxide methane 48 eruptions 48 gigatons 48 PETM 48 degree Fahrenheit 47 El Niño 47 permafrost 47 atmospheric chemistry 47 perturbations 47 latitudes 47 lake sediments 47 pikas 47 La Nina 47 meteor showers 47 milder winters 47 Pleistocene 47 Greenland ice 47 climate 47 climatology 47 earths 47 abundances 47 warmer winters 46 flu pandemics 46 El Nino 46 temperatures 46 acidification 46 manmade global warming 46 glacial ice 46 albedo 46 melting permafrost 46 geologically active 46 warming 46 tropics 46 Global warming 46 lava flows 46 climatic 46 anthropogenic global warming 45 biosphere 45 droughts 45 biodiversity hotspots 45 volcanoes 45 aridity 45 supernova explosions 45 Pliocene 45 monsoon rainfall 45 millenniums 45 tropical cyclones 45 coral bleaching 45 amphibian species 45 water vapor 45 oscillations 45 pandemics 45 volcanic earthquakes 45 aerosols 45 La Niña 45 Climatic 45 meltwater