Professor Ian Roberts, is Professor of Epidemiology & Public Heath at the London School of Hygiene & Tropical Medicine. His main research interests are the prevention and treatment of traumatic injury and the links between energy use and health. He trained as a paediatrician in the UK and then in epidemiology at the University of Auckland, New Zealand and at McGill University, Canada. He established and is co-ordinating editor of the Cochrane Injuries Group, an international network of individuals that prepares and maintains systematic reviews of the effectiveness of interventions in the prevention, treatment and rehabilitation of injury. The Cochrane Injuries Group has published over 100 systematic reviews many of which have changed clinical practice around the world. He was lead author on the systematic reviews of colloids versus crystalloids and on the use of albumin in critically ill patients, which have changed the management of critically ill patients in the NHS and world-wide. He is principal investigator of the CRASH trials, large international randomised controlled trials that seek better ways to treat seriously injured trauma patients.  The MRC CRASH trial, which included 10,000 pateints with head injury from around the world, demonstrated that corticosteroids, which were widely used in the management of serious head injury, did not improve patient outcome after head injury and actually increased the risk of death. These results have been incorporated into international treatment guidelines and have improved the safety of medical care world-wide. The CRASH-2 trial has shown that tranexamic acid, an inexpensive and widely practicable treatment, safely reduces mortality in bleeding trauma patients.

Global environmental change, in particular climate change, presents a serious threat to the stability of the ecosystems on which all human life depends. On the other hand, mitigating climate change through the decarbonisation of transport, and society more generally, presents unrivalled opportunities for improving public health. The policies that need to be implemented to reduce greenhouse gas emissions will also bring about substantial reductions in heart disease, cancer, obesity, diabetes, road deaths and injuries, and air  pollution. These health benefits arise because climate change policies necessarily impact on two of the most important determinants of health: human movement and human nutrition. Although the health co-benefits of climate change policies are increasingly recognised by health professionals they are not widely appreciated by those responsible for environmental policy. Because the existence of important health co-benefits will 

dramatically reduce the cost to society of taking strong action to mitigate climate change, failure to appreciate their importance could have serious environmental consequences. In the transport sector, the creation of safe urban environments for mass active travel will require prioritization of the needs of pedestrians and cyclists over those of motorists. Walking or cycling should become the most direct, convenient, and pleasant option for most urban trips. We have an urgent responsibility to ensure that the health benefits of wider environmental policies are understood by both the public and by policy makers.