Related by context. Frequent words. (Click for all words.) 66 glaciation 63 Little Ice Age 62 Pliocene 61 mid latitudes 61 volcanism 60 El Ninos 59 Holocene 59 Ordovician 59 lithosphere 59 mass extinctions 59 sunspot activity 58 Eocene 57 CO2 concentrations 57 Late Cretaceous 56 basalts 56 Medieval Warm Period 55 Carboniferous 55 Precambrian 55 atmospheric CO2 55 atmospheric concentrations 54 Quaternary 54 epochs 54 Cretaceous Period 54 lake sediments 54 latitudes 54 greenhouse warming 54 sunspots 53 abundances 53 Pleistocene 53 atmospheric circulation 53 polar caps 53 equatorial regions 53 landmasses 53 atmospheric carbon dioxide 53 Cretaceous 53 aerosol particles 53 sunspot 52 sediment cores 52 temperate zones 52 decadal 52 Paleozoic 52 gigatonnes 52 substorms 52 radiocarbon 52 isotopic 52 X ray emission 52 olivine 51 Greenland glaciers 51 equatorial Pacific 51 mountain glaciers 51 super Earths 51 glacial 51 glaciers 51 equinoxes 51 sedimentary rocks 51 Oligocene 51 temperate regions 51 continental drift 51 glacial melt 51 megafauna 51 diatoms 50 sediments 50 subduction zones 50 supernova explosions 50 lava flows 50 taxa 50 auroral 50 extinctions 49 albedo 49 sedimentary rock 49 upwelling 49 ejecta 49 Proterozoic 49 crustal 49 NSIDC 49 meltwater 49 species extinctions 49 calcite 49 PETM 49 greenhouse gas concentrations 49 Greenland Ice 49 volcanic eruptions 49 mammoths 49 Triassic 49 geomagnetic field 49 geologic 49 Antarctic Peninsula 49 geomagnetic 48 geologically 48 radioactive decay 48 plate tectonics 48 Miocene 48 northern latitudes 48 landforms 48 temperature gradient 48 magmatic 48 Ice Age 48 mass extinction 48 glacial ice 48 Neandertals 48 Greenland ice