I logged on to a fascinating webinar recently—medical education and climate change at the Royal Society of Medicine. As the Lancet’s 2020 Countdown on health and climate change put beyond doubt, health professionals have a major role in the global response to climate change. Mitigating the effects on health systems; identifying synergies between health promotion and carbon reduction; communicating the health impacts of climatic shift—the need for medical engagement is urgent and intensifying.

Andrew Haines, chair of The Lancet commission on planetary health—and former director of the London School for Hygiene and Tropical Medicine (LSHTM)—set out the health-related impacts. Climate change and environmental degradation are hitting health in a range of sectors: disrupting food chains; contaminating water supplies; precipitating extreme weather events; displacing disease vectors; driving respiratory disease; undermining psychological health and wellbeing. He also gave us the stark data on global warming. Despite the 2015 Paris Agreement commitment to keeping global rises in temperature “well below 2°C,” global carbon dioxide emissions have continued to rise. On current trends, global temperature is expected to rise by something in the region of 3°C by 2100, with likely catastrophic consequences for global public health. 

After setting the scene for possible apocalypse, Haines went on deftly to open a door to hope. Despite the seriousness of the challenge, there were clear opportunities for health professionals to promote change. Consider two of the main drivers of CO²—fossil fuels and animal farming, or big oil and big meat. More than three and a half million people a year die prematurely from the burning of fossil fuels. Add this to the WHO’s estimate that the combined effects of outdoor and household air pollution result in something like seven million premature deaths as year, and the role of health professionals in driving both policy and individual behaviour change is clear.

Consider meat and dairy production. Standard figures give the carbon cost of the average UK diet at 5.4 tonnes. But add in the opportunity costs associated with natural ecosystem loss from agricultural land use, as in a recent article in Nature, and it leaps to 14.4 tonnes. A landmark paper in Science suggests that a global shift to a plant-based diet would release 76 per cent of agricultural land—opening up the possibility of the widespread return of natural carbon capturing ecosystems. And then consider the health benefits of such a shift—plant-based diets are associated with reduced risks of coronary heart disease, obesity, diabetes and some cancers. The co-benefits of a global diet reset toward plants are irresistible—and health professionals have a key role to play.

Given the nature of the session, talk turned to the medical curriculum. Apparently there are three reasons for reluctance to incorporate climate change into medical teaching: insufficient room, insufficient expertise, and insufficient impact on clinical medicine. To the third, several speakers turned their thoughts. We heard from the US about Borrelia burgdorferi, better known as the bacterial cause of Lyme disease. Carried by deer ticks, its expanding range is linked to climate change. 2018 saw a 15 per cent increase in dengue transmitted by Aedes albopictus—the Asian tiger mosquito, along with regional increases in malaria and Vibrio bacteria, a strain of which can cause cholera. We heard unsettling stories of people being admitted to US hospitals suffering from heatstroke because of poorly ventilated housing—and there is no doubt that the impacts of climate change will fall heaviest on the poorest. Doctors were seeing the impact of airborne pollution on respiratory health, of climate anxiety on mental health and wellbeing, and of environmental conditions on paediatric populations. The speakers were unequivocal: climate change was relevant for clinical practice. 

Unsurprisingly though the biggest links were between climate change and public health. Our current trajectory threatens major upheaval in the underlying determinants of health. As The Lancet’s Countdown report states:

The world has already warmed by more than 1·2°C compared with preindustrial levels, resulting in profound, immediate, and rapidly worsening health effects… In the long term, climate change threatens the very foundations of human health and wellbeing.

Climate change is often presented as a matter of imminent catastrophe: Australian wildfires, the collapse of Antarctic ices shelves, Biblical plagues, wholescale inundation—an environmental eschatology. Although effective at transmitting the urgency of climate change and environmental degradation, it can lead to quietism, even paralysis. If the planetary Gods are on the move, what room for my own small actions? Yet one of the great things about the seminar was recognising the huge scope for making small positive changes. And as guardians of our individual and collective health, doctors have a key role to play. Time to address it in the medical curriculum.