My Project
Sensitivity of Pliocene Ice Sheets to Orbital Cycles
Funded by NERC
Background
Anthropogenically caused climate change is one of the major issues facing the world in the 21st Century. Warming caused by increasing greenhouse gas emissions could see the global mean temperature rise to an unprecedented level in human history; temperatures which were last recorded millions of years ago. One of the most important concerns relating to climate change is sea level rise (Hegerl et al., 2007, Meehl et al., 2007). The possible inundation of large areas of low-lying land has the potential to cause significant economic and social repercussions. Sea level rise is caused by the melting of glaciers and high latitude ice sheets, which increases the influx of freshwater into the world’s oceans, increasing the mean sea level height.
General Circulation Models (GCMs) such as those developed at the Hadley Centre and Ice Sheet Models (ISMs) now play a important role in predicting the extent of climate change and sea level rise. In order to test the ability of GCMs and ISMs to predict the likely course of the future given current conditions, it is advantageous to test the models and our understandings of the mechanisms contributing to global warmth against times in the past where similar conditions were exhibited.
My Project
According to the most recent assessment report from the Intergovernmental Panel on Climate Change (IPCC) the mid-Pliocene (about 3.3 to 3.0 million years before present; Ma BP) is an accessible interval in Earth history where conditions are similar to those predicted by climate models for the end of the 21st Century (Jansen et al., 2007). Global circulation model (GCM) results have estimated the mean planetary temperature during the mid-Pliocene warm period (MPWP) to be about 2 to 3˚C above pre-industrial temperatures. The MPWP provides an interval where the interaction of bi-polar ice sheets can be investigated in a warmer than modern climate, thus aiding our understanding of the possible range of ice sheet behaviour in the context of the future climate.
Project aims and objectives
The aim of this project is to constrain estimated volumes for the Greenland and East Antarctic ice sheets during the MPWP. The main focus of this investigation is to consider how variations in the Earth’s orbital cycles (eccentricity, precession and obliquity) will affect the amount of incoming solar radiation at the top of the atmosphere (TOA) and in turn, how this forcing mechanism will affect the behaviour of the ice sheets. Previous studies of Pliocene ice sheets have not taken into account a correct orbital configuration for c. 3 million years ago.
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