Action to Combat Climate Change Is Paramount for Healthcare

Tara Haelle

January 18, 2019

Without further action to address climate change, the impact of global rising temperatures on human health will lead to "substantial increases in morbidity and mortality," according to a review of current evidence published yesterday in the New England Journal of Medicine.

"Of particular importance for managing the associated health risks is the fact that warming will be uneven, creating different hazards in different locations," write Andy Haines, MD, of the London School of Hygiene and Tropical Medicine in the UK, and Kristie Ebi, PhD, of the University of Washington in Seattle.

In addition to illnesses resulting from heat and poor air quality, evidence suggests that decreased food quality and security will cause more undernutrition and the prevalence of vector-borne diseases will increase in some areas, Haines and Ebi warn.

"Almost two thirds of the worldwide effects of changes in atmospheric and near-surface ocean temperatures for the period 1971–2010 were attributed to anthropogenic climate change," they write after reviewing the data on increasing average global temperature and concentrations of carbon dioxide in the atmosphere. "Under some projections in some regions, toward the end of the century, the coolest day in the summer season may be warmer than the hottest day today."

They also note a swath of extreme meteorological and climate events — from heat waves to wildfires — that have resulted from a warming planet, each of which contributes its own risks to human health.

"Wildfires can increase daily air-pollution levels by as much as a factor of 10, with adverse effects on health, including an increase in respiratory disease," they write.

An accompanying editorial echoes their concerns. "Disruption of our climate system, once a theoretical concern, is now occurring in plain view — with a growing human toll brought by powerful storms, flooding, droughts, wildfires, and rising numbers of insect-borne diseases," write Caren G. Solomon, MD, deputy editor of NEJM, and Regina C. LaRocque, MD, of Massachusetts General Hospital in Boston.

"Psychological stress, political instability, forced migration, and conflict are other unsettling consequences," they continue. "These effects of climate disruption are fundamentally health issues, and they pose existential risks to all of us."

While the specific risks they discuss are well established through more than two decades of research — albeit often fragmented — on human health effects of climate change, Haines and Ebi synthesize all of this data into a single document that emphasizes the urgency of the issue and what needs to happen to address it.

Established and Emerging Risks to Human Health

The existing and anticipated effects of more frequent heat waves, poorer air quality, increased flooding from storms and sea level rise, shifts in vector-borne disease epidemiology, and increased poverty have been studied extensively. But as the climate calamity plays out, researchers have begun identifying additional threats to human health not previously recognized or appreciated until recently.

"The effects of climate change on mental health are increasingly recognized — for example, exposure to floods and other extreme events increases the risk of depression and anxiety, which may disproportionately affect people with preexisting mental health problems," Haines and Ebi write. "Increasing evidence also indicates that rising carbon dioxide concentrations have adverse effects on the nutritional quality of major cereal crops, such as rice and wheat, including lowering the levels of protein, a range of micronutrients, and B vitamins."

The nutritional effects of poorer crops and reduced vegetable and legume yield threaten prevention and management of noncommunicable disease, which may contribute to the estimated increases in mortality.

"The World Health Organization (WHO) estimated that approximately 250,000 deaths annually between 2030 and 2050 could be due to climate change-related increases in heat exposure in elderly people, as well as increases in diarrheal disease, malaria, dengue, coastal flooding, and childhood stunting," the authors note. And that conservative estimate does not include more than a half million deaths expected from reduced food availability by 2050.

The distribution and magnitude of these effects will vary according to how adequately individuals, communities, and health systems can prepare for and manage increasing health risks. Factors at play include geography, shifts in ecosystems, existing air and water quality, agricultural and livestock practices and policies, existing warning systems, and individuals' socioeconomic status, health, nutritional status, and access to effective healthcare.

Solutions Exist

Despite the evidence-based doom and gloom of Haines and Ebi's paper, they address what must happen to counteract the inevitable inability for humans to adapt to many of the coming changes — and how policy actions can begin to reap benefits right now.

Shifting eating habits away from animal-based diets and toward plant-based ones, for example, can increase environmental and health sustainability simultaneously. Reduced reliance on foods from animals can free up land and water resources, reduce greenhouse emissions by up to 30%, and decrease all-cause mortality through increased fruit and vegetable intake — actions that reduce the risk of cardiovascular disease, stroke, and several cancers.

"Increasing walking and cycling and the use of public transportation and low-emission vehicles can reduce greenhouse-gas emissions and improve health by decreasing the risk of noncommunicable disease through reduced air pollution and increased physical activity, potentially averting costs to the health system," the authors write.

Some mitigation strategies are not without risks, note Haines and Ebi. Shifting away from animal-based foods could potentially increase food prices for the poor and threaten access to protein sources. Using diesel fuel to reduce greenhouse emissions can harm health through increased pollution.

"Policies must be developed with these potential harmful effects taken into consideration and minimized," they write. Such a nuanced approach is particularly important for reforming policies related to fossil fuels, whose subsidies shield societies from the full economic cost — including health effects — of reliance on them, the authors note.

While it may seem counterintuitive for healthcare providers to have a role in energy policy, Solomon and LaRocque argue otherwise in their editorial.

"As physicians, we have a special responsibility to safeguard health and alleviate suffering. Working to rapidly curtail greenhouse gas emissions is now essential to our healing mission," they write. "Tackling this challenge may feel overwhelming, but physicians are well placed and, we believe, morally bound to take a lead role in confronting climate change with the urgency that it demands."

But they don't downplay the enormity of such an imperative in the face of the fossil fuel industry's financial incentives and the federal government's denial and inertia.

"Changing our institutions and society will therefore require concerted, organized, and forceful efforts," starting with reform to the US healthcare system, responsible for one tenth of US greenhouse emissions. "Health care professionals therefore have an ethical obligation to insist on a transformation of the way our hospitals and clinics operate."

Solomon and LaRocque note the efforts of Kaiser Permanente, Partners HealthCare, and Boston Medical Center in moving toward carbon neutrality and the success of Gundersen Health System in using wind power, solar power, and a local landfill's methane to achieve energy independence. They also called on physicians to educate others about the "links between environmental degradation and tangible problems, such as air pollution, insect-borne diseases and heatstroke."

While acknowledging the fear they feel about the climate crisis and its implications for human health and future generations, Solomon and LaRocque write they "choose to focus our efforts on areas where our voices are most powerful — for instance, by working with medical students on climate action, supporting the undergraduate divestment movement, joining forces with like-minded health professionals, and speaking with our legislators."

They also emphasize Haines and Ebi's call for revamping systems related to health outcomes vulnerable to climate change, most of which were not designed to take the effects of global warming into account.

"Some examples include the need to enhance surveillance, change the timing and location of specific vector-control measures, and adapt building codes and building locations (including locations of some health care facilities) to address rising temperatures and the risk of flooding," Haines and Ebi write.

Any approach to managing these risks must be flexible enough to adapt as health risks evolve, they add. Such a strategy also means confronting the reality that climate-related challenges will surpass humans' ability to adapt in some situations, such as extreme heat and sea level rise. 

Although actions needed extend beyond the health sector, the authors acknowledge, health professionals "can support health systems in developing effective adaptation to reduce the health risks of climate change, promote healthy behaviors and policies with low environmental impact, support intersectoral action to reduce the environmental footprint of society in general and the health care system specifically, and undertake research and education on climate change and health."

In their editorial, Solomon and LaRocque conclude with an appeal to the moral imperative they have laid out: "When the next generation asks us, ‘What did you do about climate change?,' we want to have a good answer."

No external funding was noted. Haines, Ebi, and LaRocque have disclosed no relevant financial relationships. Solomon is deputy editor of the New England Journal of Medicine.

N. Engl. J. Med. Published January 17, 2019. Full text, Editorial

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