Related by context. Frequent words. (Click for all words.) 75 mass extinction 69 extinctions 58 glaciation 58 Little Ice Age 57 atmospheric carbon dioxide 56 coral bleaching 56 volcanism 53 amphibian species 52 atmospheric CO2 52 ocean acidification 52 plate tectonics 52 volcanic eruptions 52 greenhouse gas concentrations 51 dinosaurs 50 Holocene 50 PETM 50 anthropogenic 49 diatoms 49 droughts 48 Greenland ice 48 Pleistocene 48 famines 47 floods droughts 47 oceans 47 flu pandemics 47 speciation 47 ozone depletion 47 mammals 47 biosphere 47 algal blooms 47 heatwaves 47 volcanic activity 46 Homo sapiens 46 sunspots 46 mammoths 46 cyanobacteria 46 solar flares 45 acidification 45 supernovae 45 vertebrates 45 Ice Age 45 Cretaceous 45 supernovas 45 Coral reefs 45 upwelling 45 ecosystems 45 gamma ray burst 44 glaciers 44 phytoplankton 44 eutrophication 44 lava flows 44 amphibians 44 global warming 44 coral reefs 44 climatological 44 species 44 Eocene 44 meteor showers 44 Earths 44 gamma ray bursts 44 fossil 43 marine ecosystems 43 cataclysmic 43 Global warming 43 millennia 43 comets 43 pandemics 43 strandings 43 eruptions 43 perturbations 43 epochs 43 landforms 43 catastrophes 43 volcanoes 43 hominids 43 climatic 43 extinction 42 Droughts 42 sauropods 42 Triassic 42 phenomena 42 organisms 42 mammal species 42 eukaryotes 42 sunspot 42 rocky planets 42 earthquakes 42 acid rain 42 ocean ecosystems 42 supernova 42 evolutionary 42 paleo 42 Global Warming 42 perturbation 42 cosmologists 42 lichens 42 evolutionary biologists 42 algae blooms 42 polar regions 41 coral species 41 plankton