The last time in Earth’s history that atmospheric CO2 levels were as high as today (~400 ppmv) was the mid-Pliocene (~3.3 to 2.9Ma), a period that preceded the onset of extensive northern hemisphere glaciation and that was characterized by global mean temperatures as much as 3 °C warmer than the present. Thus, understanding the mid-Pliocene warm period (MPWP) allows us to explore climate sensitivity and polar ice sheet stability in a slightly warmer world. Indeed, the MPWP has served as a target for the testing of climate and ice sheet models designed to predict the future response of Earth’s climate to increasing levels of greenhouse gases. However, the evaluation of climate model results has been hampered by the limitations of the available paleoclimate data sets and, in particular, by uncertainty in the proxies used to investigate the maximum eustatic sea level (or minimum polar ice volume) attained during the MPWP. Estimates for peak MPWP sea level range from10 to 35m above the present and a value of 25m has been typically adopted in numerical climate model simulations. Field observations that can provide constraints on sea level during the MPWP are few in number and, until recently, were rarely corrected for the effects of glacial isostatic adjustment or dynamic topography. It is now recognized that such corrections must be made before estimates of local sea level can be mapped into a rigorous estimate of globally averaged, or eustatic sea level in the Pliocene.
In this topic we work to answer the question: how high was sea level in Mid-Pliocene?
- Collaboration with PLIOMAX – Pliocene Sea Level Maximum (US National Science Foundation)
- Maureen E. Raymo, LDEO, Columbia University, US
- Paul J. Hearty, UNC Wilmington, US
- Jerry X. Mitrovica, Harvard, US
- Jacqueline Austermann, Harvard, US
- Field collaborators in different areas
Publications (since March 2014)
Rovere, A., Hearty, P.J., Austermann, J., Mitrovica, J.X., Gale, J., Moucha, R., Forte, A.M., Raymo, M.E., 2015. Mid-Pliocene shorelines of the US Atlantic Coastal Plain — An improved elevation database with comparison to Earth model predictions. Earth-Science Rev. 145, 117–131. doi:10.1016/j.earscirev.2015.02.007