A critical evaluation of the Paleocene-Eocene Thermal Maximum: an example of things to come?

Abstract

The Paleocene-Eocene Thermal Maximum (PETM), arguably the most dramatic hyperthermal event recorded to date, occurred approximately 55 million years ago (Ma). During this event thousands of petagrams of carbon were released into the atmosphere and hydrosphere affecting the climate, ocean chemistry and marine and terrestrial ecosystems. With a duration of approximately 100,000 years (though possibly as long as 170,000 years) and global temperature increases of between 4- 8°C, terrestrial and marine faunal turnover occurred including mammalian dispersal, rapid evolutionary and ecological change and transient diversification. The PETM, therefore, offers a valuable insight into shifts in the climate regime and the resultant marine and biotic response that may be relevant to future anthropogenically induced climate change. The mechanisms for delivery of isotopically light carbon into the atmosphere and hydrosphere remain a hotly debated topic. Here we discuss numerous p