Paul is an Environmental Health Scientist. His research interests include impacts of climate change on human health, with a particular focus on allergens and allergic diseases. It is for this research that he won the 2009 Eureka Prize for Medical Research. Paul was also a contributing author of the Intergovernmental Panel on Climate Change's (IPCC's) Fourth Assessment Report published in 2007, the same year the IPCC won the Nobel Peace Prize. Paul is currently the Acting Head of the Department of Environment and Geography and the immediate Past President of the International Society of Biometeorology (having served as President from 2008-2011).