Related by context. Frequent words. (Click for all words.) 60 Pleistocene 58 Little Ice Age 57 glaciation 57 Eocene 54 volcanism 51 atmospheric CO2 51 Triassic 50 mass extinctions 50 mass extinction 50 Cretaceous 49 Jurassic 48 paleo 48 isotopic 47 atmospheric carbon dioxide 46 glacial 46 diatoms 45 geologic 45 Miocene 45 Homo sapiens 44 greenhouse warming 44 Paleolithic 44 millennia 44 Neolithic 44 hunter gatherers 44 sunspot 44 latitudes 44 anthropogenic 43 El Niño 43 greenhouse gas concentrations 43 prehistory 43 PETM 42 epochs 42 Fossils 42 equatorial Pacific 42 hominids 42 atmospheric 42 Neanderthals 42 taxa 41 Ice Age 41 climatic 41 upwelling 41 extinctions 41 climatological 41 Bronze Age 41 sediments 41 La Niña 41 albedo 40 Tibetan Plateau 40 radiocarbon dating 40 Antarctic Peninsula 40 northern latitudes 40 Industrial Revolution 40 Antarctic Ice 40 fossil 40 plate tectonics 40 millenniums 40 Archean 40 biosphere 40 speciation 40 Hellenistic 40 permafrost 39 geologically 39 oceanic 39 prehistoric 39 Gondwana 39 sedimentary 39 La Nina 39 glacial ice 39 Glacial 39 boreal 39 Greenland ice 39 tectonic 39 ocean acidification 38 Antarctic ice 38 caldera 38 glaciers 38 El Nino 38 sedimentary rocks 38 perturbation 38 Devonian 38 streamflow 38 polar ice 38 hunter gatherer 38 Iron Age 38 polar 38 millenia 38 mammoths 37 Martian 37 fossils 37 basalt 37 sunspots 37 martian 37 colonization 37 equatorial 37 volcanic activity 37 Neanderthal 37 Roman Empire 37 equinox 37 Homo erectus 37 epoch 37 acidification