Pliocene Research, Interpretation and Synoptic Mapping (PRISM) 3D Reconstruction

Estimates of middle Pliocene (~3.0 Ma) global warming suggest temperatures were 2°C greater than today. This level of warming is within the range of the Intergovernmental Panel on Climate Change (IPCC) estimates of global temperature increases for the 21st century, and no other time period in the past 3 million years approaches this level of warming. Scientists have identified many primary forcing mechanisms that contribute to the current global warming, but there is uncertainty about the relative impact of each forcing and associated feedbacks. The middle Pliocene presents the reverse situation: global data sets reveal the mature state of a warmer world, but the forcings that led to Pliocene warming are only partially identified. The data so far compiled by the Pliocene Research, Interpretation and Synoptic Mapping group (PRISM) suggest a combination of increased greenhouse gasses and increased ocean heat transports acted concurrently through undetermined feedback relationships. Global Warming Analysis - PRISM 3D is a collaborative data analysis and climate modeling effort. The primary goal is to create three-dimensional global data sets of mid-Pliocene ocean temperature and salinity, which will form the most comprehensive global reconstruction for any warm period prior to the recent past. The data sets will be then used to drive numerical simulations designed to explore the impact of climate forcings and feedbacks during the middle Pliocene. The middle Pliocene world provides an unequaled paleo-laboratory to test the sensitivity of the physical models that we rely upon for estimating future warming impacts. It challenges our understanding of the sensitivity of key components of the climate system and how we simulate that system: polar vs. tropical sensitivity, the role of ocean circulation in a warming climate, the hydrological impact of altered storm tracks, and the regional climate impacts of modified atmospheric and oceanic energy transport systems.

PRISM3D is the main USGS contribution to this collaborative effort. PRISM3D is planned to incorporate improvements to the SST and Sea-Ice data sets as well as increased coverage in the Vegetation data set. The SST data has been enhanced by the construction of maximum and minimum probable warming data sets that bracket the range of variability in the Pliocene SST. The most significant change will be the inclusion of deep-water temperatures and salinities and a three-dimensional ocean. The next generation of fully coupled ocean-atmosphere general circulation models require a 3-D ocean and this will be a major improvement to the PRISM data set allowing use in more sophisticated future-climate modeling experiments.

Data for the Atlantic Ocean Minimum and Maximum SST are available.