• DOI:10.1038/357320A0
• Corpus ID: 4348331

Possible methane-induced polar warming in the early Eocene

@article{Sloan1992PossibleMP,
  title={Possible methane-induced polar warming in the early Eocene},
  author={Lisa Cirbus Sloan and JAMES C. G. Walker and Theodore C. Moore and David Kenerson Rea and James C. Zachos},
  journal={Nature},
  year={1992},
  volume={357},
  pages={320-322}
}

• L. Sloan, JAMES C. G. Walker, +2 authors J. Zachos
• Published 28 May 1992
• Environmental Science
• Nature

RECONSTRUCTIONSof early Eocene climate depict a world in which the polar environments support mammals and reptiles, deciduous forests, warm oceans and rare frost conditions 1–5. At the same time, tropical sea surface temperatures are interpreted to have been the same as or slightly cooler than present values6. The question of how to warm polar regions of Earth without noticeably warming the tropics remains unresolved; increased amounts of greenhouse gases would be expected to warm all latitudes equally7. Oceanic heat transport has been postulated as a mechanism for heating high latitudes8–10, but it is difficult to explain the dynamics that would achieve this7,11. Here we consider estimates of Eocene wetland areas and suggest that the flux of methane, an important greenhouse gas, may have been substantially greater during the Eocene than at present. Elevated methane concentrations would have enhanced early Eocene global warming, and also might specifically have prevented severe winter cooling of polar regions because of the potential of atmospheric methane to promote the formation of optically thick, polar stratospheric ice clouds12–14.