NCAS climate variability and change group

Through our research we aim to develop an integrated understanding of climate variability and change on timescales from seasonal to millennial. Our emphasis is on understanding processes within the coupled climate system.

The world's climates have changed over the last 100 years, and the northern hemisphere is probably warmer now than at any time in the last millennium. Climate change due to human activity is very likely to be larger in the coming century. Internally generated climate variability can also have large socio-economic impacts, prominent examples being El Niño and the North Atlantic Oscillation. Understanding how and why climate varies is the fundamental issue of climate science and of the utmost practical importance.

The group is part of NCAS-Climate@Reading and the Walker Institute. Our work is funded by the National Centre for Atmospheric Science, and by other research grants, notably from the NERC RAPID and QUEST programmes. Current research interests include:

• Decadal predictability and prediction. The climate of the next few decades will be shaped by an interplay between the signal of anthropogenic climate change and natural variability. Our research aims to improve understanding of both these components and the extent to which they are predictable. We collaborate with the Met Office Hadley Centre on the development of decadal prediction capabilities.
• The role of the Atlantic Ocean in the global climate system. The Atlantic Ocean transports approximately 1PW heat northwards. Variations in the heat transport on decadal timescales are particularly associated with the Atlantic Meridional Overturning Circulation (AMOC). Our research aims to understand the processes that govern variability in the AMOC, and the subsequent effects on the climate locally and further affield.
• Projection of changes in the AMOC for the coming century. Comparative analysis of models will help focus attention on ill-quantified aspects of the system and thus lead to better understanding of the processes and a reduction in the large uncertainty that current exists in these projections.
• Earth system modelling. Extension of predictive global atmosphere-ocean models to include interactions with atmospheric chemistry, terrestrial ecosystems and marine biogeochemistry. Studies of the variation of climate over the last glacial cycle. The aim of these developments is to investigate the feedbacks among Earth system components that may be important in past and future climate change.
• Projection of future sea level change, which is an important impact of climate change. Sea level is affected by heat uptake by the ocean causing thermal expansion, and changes in the volume of ice-sheets and glaciers.
• Sensitivity of climate to radiative forcing, and how this can be constrained by past climate change.