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Strong chemistry‐climate feedbacks in the Pliocene
Author(s) -
Unger Nadine,
Yue Xu
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl058773
Subject(s) - carbon dioxide in earth's atmosphere , environmental science , climatology , paleoclimatology , global cooling , aerosol , vegetation (pathology) , atmospheric sciences , biome , climate sensitivity , climate model , carbon dioxide , albedo (alchemy) , ozone , climate change , ecosystem , geology , oceanography , meteorology , geography , ecology , medicine , art , pathology , performance art , biology , art history
The Pliocene epoch was the last sustained interval when global climate was significantly warmer than today but has been difficult to explain fully based on the external forcings from atmospheric carbon dioxide and surface albedo. Here we use an Earth system model to simulate terrestrial ecosystem emissions and atmospheric chemical composition in the mid‐Pliocene (about 3 million years ago) and the preindustrial (~1750s). Tropospheric ozone and aerosol precursors from vegetation and wildfire are ~50% and ~100% higher in the mid‐Pliocene due to the spread of the tropical savanna and deciduous biomes. The chemistry‐climate feedbacks contribute a net global warming that is +30–250% of the carbon dioxide effect and a net aerosol global cooling that masks 15–100% of the carbon dioxide effect. These large vegetation‐mediated ozone and aerosol feedbacks operate on centennial to millennial timescales in the climate system and have not previously been included in paleoclimate sensitivity assessments.