Hannah Nissan

Willis Towers Watson

Associate Director of Research in the Climate and Resilience Hub

Hannah Nissan is Associate Director of Research in the Climate and Resilience Hub at WTW and a Visiting Senior Fellow at the Grantham Research Institute for Climate Change and the Environment at the LSE. She specializes in the development and use of climate and weather services to manage the public health impacts of climate variability and change. She has worked with national and regional meteorological services in the Caribbean and South Asia to tailor and translate heat forecasts and science for practical use and has extensive experience in capacity building to support policy- and decision-makers to incorporate science effectively into policy and practice. At WTW she leads work on climate and health, working with employers, insurers and the public sector to manage the health risks associated with climate variability and change.


Hannah formerly held research positions at the London School of Economics and Political Science, the International Research Institute for Climate and Society (IRI) at Columbia University, where she was a Lloyds’ of London – Fulbright Scholar and an Earth Institute Fellow, and Imperial College London. From 2018-2020 she was Director of the WHO Collaborating Centre for Early Warning Systems for Malaria and Other Infectious Diseases at IRI, where she supported the WHO in its work on climate change and health. She has worked as a consultant on climate and disaster risk management for a range of organizations including the Wellcome Trust and currently serves on the American Meteorological Society’s Board on Environment and Health. Hannah holds a PhD in Climate Modelling from Imperial College London, a Postgraduate Diploma in Economics from the University of Cambridge and a BSc in Physics from the University of Bristol.