The age of anthropogenic disease

When Eugene Stoermer and Paul Crutzen popularised the use of the word Anthropocene in 2000, they might not have known it would become an unofficial designation for a geological epoch marked by human impact on the planet's climate, geology, and ecosystems. The term now encompasses a long list of man-made changes to the environment, which are increasingly affecting not just planetary homoeostasis, but humanity's health too. Diseases in the Anthropocene are taking unprecedented turns, affecting how people live, age, and die. For instance, temperature extremes, both hot and cold, are associated with an increased risk of mortality from a variety of cardiovascular conditions. Infectious diseases are shifting geographically, with a warmer climate leading to billions more people becoming susceptible to mosquito-borne diseases. New data also show that some conditions are exacerbated by less extreme changes to our environments: for example, chronic exposure to outdoor night-time artificial light can increase the risk of impaired glucose metabolism and the prevalence of diabetes, and also correlates with a decrease in sleep duration in older adults—which can elicit a variety of sleep disorders, metabolic disturbances, and increased propensity to falls. Another example is the recently reported association between exposure to fine particulate matter (PM) and the incidence of dementia. However, even as evidence accrues to show that human-induced changes to our environment impact our health as well as our planet, such data are not translating into policy or action, as attested to by successive disappointing instances of the UN Climate Change Conference. Modelling and monitoring have shown that extreme weather events, the frequency of which has climbed steeply over the past 20 years, would be highly unlikely without human interference via human-induced climate change. Heatwaves alone have killed hundreds of thousands of people in recent years, including 70 000 people in Europe during a single heatwave in 2003, and 54 000 in the hot and humid summer in Russia in 2010—not regions usually thought of as reaching dangerously high temperatures. Electric lighting only began to be used widely at the end of the 19th century and has undoubtedly brought benefits to humankind, from reducing exposure to fumes and residues from older lighting methods, to making societies more productive—but we might now be paying a price as over-illumination and light pollution alter our very metabolism. The yet-unresolved dependence on fossil fuels for both transportation and industry means that there is no easy solution for the vast amounts of PM2·5 being pumped into the atmosphere at every moment—even though PM has been known to be a major contributor to global morbidity and mortality for decades. A stark failure to deal with these ubiquitous threats is exemplified by a recent report on levels of pollution inside the London Underground, which found that air pollution in the city's subterranean transport grid was ten times higher than WHO recommended levels—making a network used daily by nearly 5 million people perhaps the most polluted place in the city, and probably contributing to the more than 9000 premature deaths caused by air pollution in London every year. When such observations are taken together with newer avenues of research, such as those suggesting a link between ingestion of microplastics and inflammatory bowel disease and increased susceptibility to infectious disease, a disheartening picture of the future of human health starts to emerge. Even as governments worldwide keep ostensibly trying to adhere to planetary warming limits and adapting to climate change, measures are coming too little and too late. Some steps are being taken in the right direction, such as several major cities implementing zero or near-zero emission zones and the Biden Administration setting goals for a net-zero emissions economy in the USA by 2050, but the pace of progress is still too slow, and the incidence of anthropogenic diseases is likely to rise rather than fall. Coupled with globally ageing populations, which will see an increase in non-communicable and age-related diseases, a synergistic public health disaster, for which global health systems are unprepared, is to be expected. 2 years ago, in our January 2021 Editorial, we reflected on how there can be no healthy longevity without a healthy planet. If any doubt remained that immediate action is required to tackle the survival challenges that both humans and the planet face, the new plethora of disease in the age of the Anthropocene will soon drive the consequences of inaction into our last refuge: our very own bodies. COP27: a “collective failure”Although a deal has been struck on compensation, health experts criticise the lack of progress on fossil fuels. Nayanah Siva reports. Full-Text PDF