HIGH-LATITUDE WETLANDS AS A SOURCE OF METHANE AND DRIVER OF SHORT- AND LONG-TERM CLIMATE CHANGE IN THE EOCENE GREENHOUSE WORLD
The Eocene is also characterized by long-term warming leading up to the Early Eocene Climatic Optimum (EECO), and gradual cooling from the EECO to the early Oligocene. It is possible that such temperature changes could also be driven in part by variable methane emissions from high-latitude +/- other wetlands, with the areal extent of these wetlands playing the critical role as a feedback mechanism. The expectation would be wetland expansion associated with increasing global temperatures, and wetland contraction associated with decreasing temperatures. Although present-day ice cover makes it difficult to map changes in the extent of high-latitude wetlands in detail, a general decrease can be inferred from the EECO to the early Oigocene.
Overall this research suggests an intriguing possibility: that methane production in high-latitude wetlands of the greenhouse played a feedback role in the climate system that is analogous to that played by high-latitude ice sheets of the present-day icehouse. Ongoing study of this possibility may lead to a better understanding of the Eocene as well as a better understanding of what a warmer, future world may look like.