London School of Hygiene & Tropical Medicine

Professor Sir Andy Haines

The UN IPCC Working Group 1 report emphasises the now unequivocal evidence for human induced climate change with an increase in global average temperature in excess of 1°C since 1850 when temperature records began.

It summarises how the emissions of carbon dioxide and short-lived climate pollutants such as methane have been responsible for the changes in climate and gives assessments of the likelihood that observed changes in outcomes such as the reductions in Arctic sea ice, glacier retreat, sea level rise and changes in precipitation are due to climate change.

The implications for health are of particular concern and will be addressed in Working Group 2 report next year. There is growing evidence that climate change is affecting health already and will do so increasingly in the future.

Over 30% of heat-related deaths over recent decades in a range of sites around the world can be attributed to climate change. The ability of mosquitoes to transmit dengue has increased in recent decades as a result of the changing climate. Crop yields are declining and the production of vegetables, fruit, nuts and seeds, essential for a healthy diet are projected to decrease in some regions. Wildfires have ravaged Australia, Canada, USA, Greece and other countries in the recent past, exposing large populations to toxic smoke and destroying biodiversity.

Climate change is not just a threat to the environment it is also damaging health in many ways. In the absence of effective action, health effects such as these will get worse and may exceed the ability of populations to adapt to the changing climate.

The good news is that many of the actions we need to take to cut greenhouse gas emissions will improve health in the near term as well as reducing the risks of dangerous climate change. Burning fossil fuels such as coal and oil large causes large amounts of air pollution responsible for several millions of deaths annually. Using clean renewable energy from solar or wind avoids the release of both greenhouse gases and air pollutants.

Encouraging walking and cycling as well as the use of public transport reduces air pollution and brings the benefits of physical activity that in turn reduces the risks of conditions such as heart disease, stroke and diabetes. The food system is responsible for about 30% of greenhouse gas emissions and unhealthy diets also increase the risk of premature death – incentivising healthy dietary choices, especially predominantly plant based diets, improves health and reduces greenhouse gas emissions. Retrofitting houses with improved insulation, shading and ventilation can reduce greenhouse gas emissions improve comfort and health.

Overall, there are many opportunities to cut greenhouse gas emissions rapidly and improve health. Reframing climate change as a health issue – both a threat and an opportunity can accelerate action towards a net zero economy over coming decades.