Complex sentence: He was Co-convening Lead Author (with Jonathan M. Gregory) for the Chapter on Sea Level in the IPCC Third Assessment Report and a member of the Joint Scientific Committee of the WCRP.
Split into simpler sentences: He was Co-convening Lead Author (with Jonathan M. Gregory) for the Chapter on Sea Level in the IPCC Third Assessment Report. He is a member of the Joint Scientific Committee of the WCRP.