A key problem for reducing the uncertainty in climate projections is historical records of change are often too short to test the skill of climate models, raising concerns over our ability to successfully plan for future change. Published records only allow a robust reconstruction of global temperature back to around 1850 and show a ‘gradual’ warming trend of around 0.8°C. However, a wealth of geological, chemical, and biological records clearly indicate large changes in the climate system took place in the past. The forcing associated with these changes appear to have been relatively small, implying the associated thresholds (often described as ‘tipping points’) are considerably smaller than generally supposed. Gradual variations in the global climate on decadal to millennial timescales allow us to study the sensitivity of the climate system to external forcings, improving our estimates of the response to increasing concentrations of atmospheric greenhouse gases.
Against a backdrop of enhanced anthropogenic-driven climate change, it is essential we have a better understanding of the earth-ocean-atmosphere system. The Palaeoclimate Science team in the CCRC is actively researching a number of competing theories and models of annual to millennial-scale change, aiming to better understand the global system. By generating highly precise and accurate climatic changes from around the world, we are working to test the degree to which changes were synchronous (or not) across a range of periods in the geological past, and identify the mechanisms by which the climate signals were propagated globally. These results are critical for improving our ability to reduce future uncertainty.
The principal areas of research include:
- Modelling the Earth system using a range of models with varying degrees of complexity;
- Modelling of climate-carbon cycle interactions on glacial to centennial timescales;
- Investigating the mechanisms, feedbacks and thresholds underlying past abrupt climate events;
- Reconstructing past ice sheet extent and their contribution to global sea level;
- Exploring the role of Southern Hemisphere Westerlies (SHW) on ocean circulation and the carbon cycle;
- Reconstructing different modes of climate, including the Southern Annular Mode (often abbreviated to SAM); the El Niño-Southern Oscillation (ENSO) and the East Asian Monsoon (EAM);
- Terrestrial, ice and marine climate reconstruction for key periods including the last 2000 years, the termination of the last glacial period (Termination 1) and the Last Interglacial (Stage 5e);
- Climate forcing, including volcanic and solar, ocean gateways and their influence on the evolution of the planet’s climate; and
- Improved methods for climate reconstruction, chronological control and data-model comparison.