Sam is the Chief Scientist for the Climate and Atmosphere Centre. He is an expert on using climate models to understand the drivers of climate variability in New Zealand and Antarctica, and in particular human-induced climate change. His research has been able to identify the contribution of human-induced warming to intensifying current New Zealand weather extremes, including droughts and floods. Recently he has been part of a team investigating the interactions between Antarctic sea-ice, atmospheric circulation and the Southern Ocean. He joined NIWA in 2006 and commenced his current role as Chief Scientist in 2015.