Related by context. Frequent words. (Click for all words.) 64 glaciations 62 interglacial period 58 interglacial 56 subarctic 55 polar vortex 54 deglaciation 54 glaciation 54 Younger Dryas 53 equatorial Pacific Ocean 53 El Niños 53 geomagnetic field 52 Cretaceous Period 52 lithosphere 52 Equatorial Pacific 52 photosphere 51 Polar Regions 51 Dry Valleys 51 degrees Fahrenheit warmer 51 solar nebula 51 Snowball Earth 51 solar irradiance 51 Alpine glaciers 50 sunspot cycle 50 retreating glaciers 50 Little Ice Age 50 substorm 50 cryosphere 50 severe droughts 50 Archaean 50 atmospheric methane 50 Petermann Glacier 50 El Niño Southern Oscillation 50 mid latitudes 50 Weddell Sea 50 El Ninos 49 Volcanic eruptions 49 Holocene 49 Snowfall amounts 49 heavily cratered 49 Lake Vostok 49 mesosphere 49 icecap 49 central equatorial Pacific 49 Upper Paleolithic 49 NSIDC 49 eastern equatorial Pacific 49 coronal hole 48 storminess 48 Maunder Minimum 48 terrestrial ecosystems 48 meteorite impacts 48 Relative humidity 48 Beringia 48 sunspot numbers 48 Jurassic Period 48 Pleistocene 48 circular orbits 48 substorms 48 continental crust 48 temperate forests 48 Cenozoic 48 Early Cretaceous 48 icy moons 48 primate evolution 48 receding glaciers 47 El Nino warming 47 Late Cretaceous 47 subtropical regions 47 poleward 47 placental mammals 47 hydrothermal activity 47 sunspot activity 47 Pacific Decadal Oscillation 47 obliquity 47 glacial retreat 47 Permafrost 47 hydrological cycle 47 paleoclimate 47 noctilucent clouds 47 basalts 47 geomagnetic 47 Arctic Oscillation 47 Late Triassic 47 oceanic crust 47 igneous rocks 46 Ross Ice Shelf 46 By GREG SMITH 46 Ordovician 46 atmospheric circulation 46 temperate zones 46 manmade greenhouse gases 46 atmospheric CO 46 Tonight Cloudy 46 warmer wetter 46 Ellesmere Island 46 Carboniferous 46 Paleocene 46 epochs 46 glacial 46 clathrates 46 Biogeography