A Chief Research Scientist at CSIRO and CSIRO Office of Chief Executive Science Leader, specializes in research into global climate variability and change. With over 20 years of research and leadership experience, his interest spans from dynamics of  modes of climate variability (such as El Niño-Southern Oscillation, the Indian Ocean Dipole) and their mechanisms, to climate detection and attribution, through to impacts of individual forcing factors of increasing carbon dioxide, increasing anthropogenic aerosols, and stratospheric ozone depletion.  His service to science communities includes a contributing author to IPCC AR4 and AR5 reports, co-Chair of World Climate Research Programme CLIVAR Pacific Panel during 2009 – 2015, and Director of CSIRO Earth System Assessment programme (2013-2016).