I am Professor of Environmental Change and Public Health with a joint appointment in the Dept of Public Health, Environments and Society and in the Dept of Population Health. I  was previously Director (originally Dean) of LSHTM for nearly 10 years up to October 2010, having previously been Professor of Primary Health Care at UCL between 1987-2000. I worked part-time as a general practitioner in North London for many years.

Between 1993-6 I was on secondment as Director of Research & Development at the NHS Executive, North Thames and I was consultant epidemiologist at  the MRC Epidemiology and Medical Care Unit between 1980-7.  I have also worked internationally in Nepal, Jamaica, Canada and the USA.

I have been a member of a number of major international and national committees including the MRC Global Health Group ( chair) and the MRC Strategy Group. I was formerly chair of the Universities UK Health and Social Care Policy Committee and a member of the WHO Advisory Committee on Health Research. In recent years my research focus has been on the effects of environmental change on health and the impact of policies to adapt to or mitigate these changes.  I was a member of Working Group 2 of the UN Intergovernmental Panel on Climate Change for the second and third assessment reports and review editor of the health chapter in the fifth assessment report. I chaired the Scientific Advisory Panel for the 2013 WHO World Health Report on Research for Universal Health Coverage. In 2014/2015 I chaired the Rockefeller Foundation/Lancet Commission on Planetary Health and I co-chaired the development group for the Health Knowledge Action Network of Future Earth.   I was co-chair of the European Academies Science Advisory Committee working group on climate change and health in Europe which published its report in June 2019. I currently co-chair the InterAcademy Partnership(~140 science academies worldwide) working group on climate change and health and the Royal Society/ Academy of Medical Sciences group on health and climate change mitigation.I also co-chair the Lancet Pathfinder Commission on health in the zero-carbon economy and participate in the Lancet Commissionon Pollution and the Lancet Commission on the COVID-19 response.