University of Tasmania, Australia

Improving the projections of future sea-level rise

In 2007, the Intergovernmental Panel on Climate Change (IPCC) summarised projections of sea-level, indicating that sea-level may rise by up to about 0.8 metres during the 21st century. However, if these models are used to simulate sea-level rise during the 20th century, they significantly underestimate the observed rise. Further, observations of current sea-level rise also suggest that the model projections may be underestimates, although the present relatively high level of rise (about 3.1 mm/year) may be simply part of a natural multi-decadal oscillation. Until recently, it was difficult to diagnose problems in models of sea-level rise because the individual components of the observed rise (e.g. thermal expansion and melting of land ice) were not well understood.

However, a recent paper by Domingues et al (2008) and more recent updates have provided estimates of the individual components which are consistent with the overall observed sea-level change.

This project will use models employed for the IPCC projections (both global climate models (GCMs) and simpler models like MAGICC) to simulate sea-level rise during the 20th century. Simulations of individual sea-level rise components will be compared with the estimates of Domingues et al (2008), indicating where problems may exist in the models. This diagnosis should lead to improved simulation of these components and consequent improvements in the projections of future sea-level rise.