Climate modelling plays a fundamental role in the study of the past two millennia. Models simulate the processes that occur within the climate system, and therefore provide a dynamical framework within which to understand past changes. By integrating climate model simulations with proxy data, it is possible not only to evaluate and constrain the models, but also to generate new insights into the nature of the climate system.

This poster will present results from climate modelling work conducted on behalf of the PAGES Aus2k Working Group. A climate system model is used to simulate the evolution of the global climate over the past 2,000 years. Different combinations of natural and anthropogenic forcings are applied, including changes in the Earth's orbital parameters, solar irradiance, volcanic emissions and greenhouse gas concentrations.

The model simulations are compared with high-resolution proxy data for the Australasian region. The comparison considers changes in both the mean state of the climate and the dominant modes of climate variability, particularly El Niño-Southern Oscillation. The model simulations are also used to assess the relative roles of different forcings in driving past climate variability and change, as well as to explore the physical mechanisms involved.