Related by context. Frequent words. (Click for all words.) 69 atmospheric CO2 69 atmospheric carbon dioxide 64 volcanism 63 greenhouse warming 61 atmospheric concentrations 61 mass extinctions 60 methane 59 greenhouse gas concentrations 59 meltwater 58 anthropogenic 58 water vapor 57 extinctions 57 sunspot activity 57 mid latitudes 57 atmospheric circulation 56 glaciation 56 glaciers 56 phytoplankton 55 ozone depletion 55 radioactive decay 55 mountain glaciers 55 Carbon dioxide 54 volcanic activity 54 Tibetan Plateau 54 melting permafrost 54 abundances 54 albedo 54 permafrost 54 carbon dioxide 54 Little Ice Age 54 heat trapping carbon dioxide 53 mass extinction 53 atmospheric chemistry 53 atmospheric 53 Greenland ice 53 aerosols 53 isotopic 53 plate tectonics 52 salinity 52 seismicity 52 troposphere 52 magma 52 diatoms 52 Antarctic ice 52 volcanic eruptions 51 magmatic 51 Sulfur dioxide 51 crustal 51 oceans 51 polar regions 51 sediments 51 biosphere 51 Serreze 51 earths 51 sunspots 51 upwelling 51 carbon dioxide CO2 51 Medieval Warm Period 51 olivine 51 megafauna 51 Greenhouse gases 50 Enceladus 50 glacial 50 Pliocene 50 gigatons 50 supernova explosion 50 ejecta 50 geomagnetic field 50 volatiles 50 acidification 50 Holocene 50 decadal 49 extrasolar planet 49 gamma ray burst 49 Nature Geoscience 49 radiocarbon 49 carbon dioxide methane 49 snowpack 49 organic compounds 49 greenhouse gases 49 Antarctic Ice 49 earth crust 49 sediment cores 49 heat trapping 49 streamflow 49 glacial ice 49 sediment 49 single celled organisms 49 lava flows 48 nitrogen 48 nitrous oxide emissions 48 hydrothermal 48 CO2 48 supernovae 48 amphibian species 48 archaea 48 sunspot 48 peat bogs 48 ozone concentrations 48 volcanic earthquakes 48 gases