PLIOMAX: Pliocene maximum sea level project

Abstract

Accurate estimates of mid-Pliocene sea levels are necessary if we are to better constrain Greenland and Antarctic ice sheet stability in a warmer world. The mid-Pliocene climate optimum (3.3-2.9 Ma) provides both a natural analog and a testing ground for General Circula-tion Models (GCMs) used for prediction of global warming. However, the value of such model experiments is governed by the quality of available paleoclimate data, and no more important metric of global climate exists than polar ice volume. Es-timates of mid-Pliocene sea level range from +5m to >+40m (" + " represents the elevation of sea level relative to present) reflecting a huge range of uncertainty in the sensitivity of polar ice sheets, includ-ing the East Antarctic Ice Sheet (EAIS), to a modest global warming. It is the aim of the PLIOMAX project to reduce the level of uncertainty in Pliocene ice-volume es-timates by undertaking a field geology program in Australia and engaging, in part through a web-based collaborative, a larg-er community of geoscientists in surveys of similar high-stand deposits around the world. Determination of the maximum mid-Pliocene sea level rise will allow cli-mate modelers to better assess the level at which atmospheric CO 2 concentrations might lead to significant melting of the Greenland Ice Sheet, West Antarctic Ice Sheet (WAIS), and EAIS.