O’Neill works to bridge the physical science of climate change with research into population demographics and other socioeconomic issues. His specialty, known as integrated assessment modeling, addresses such questions as whether an aging population will naturally tend to engage in activities that emit fewer greenhouse gases and the extent to which emissions are likely to increase because of the increasing urbanization of developing countries. He also studies the challenges faced by policy makers in addressing climate change when some of the impacts of global warming are longterm and uncertain.
