My general research interests are in the field of climate change and climate variability on time scales ranging from seasonal-interannual to glacial-interglacial cycles. My approach is to study the Earth system as a whole, focusing on the interactions among various components, in particular, the atmosphere, the hydrosphere and the biosphere. Currently my research covers two different but inter-connected areas: carbon cycle-climate interaction and the modeling of atmosphere-land-vegetation-ocean system. I also conduct research in the technical solutions and policy implications of climate change, including renewable energy and carbon sequestration.