Connecting Climate Change and Health

Upon examination it became clear that the man, a farmer from Central America, was suffering from kidney failure and required immediate hospitalization and dialysis. It turned out that he had chronic kidney disease, which typically isn’t seen in such young patients, Basu said.

The case prompted Basu to more deeply study a phenomenon known as “Mesoamerican nephropathy,” which his patient was diagnosed with.

“A body of research makes a compelling case that my patient’s health was upended because of the impact of chronic, severe heat on his kidneys. If you are out in the heat, working in the farms day in and day out, year after year, often wearing heavy clothing, you become dehydrated. And this can impact the blood perfusion to your kidneys. And slowly but significantly, it can cause severe chronic kidney disease and even require dialysis at a young age,” he said.

“I started asking myself, what were the ways in which I was missing the dangers of severe heat on my other patients. Was I asking if patients had cooling systems in their homes during heat waves? Was I asking my patients who are outdoor laborers if they had work protections from prolonged exposures to dangerous heat? I realized I needed to do a better job in my primary care clinic,” Basu said.

“I can’t say that climate change caused this patient’s disease — that’s not the way it works — but it increases the risks. It makes it more likely,” he said. “Once we see the connections, it’s hard to unsee them.”

Climate change in the MD curriculum

For Basu, Malits, Baker, and a wider group of HMS students, the threat climate change is posing to human health is no longer theoretical but a very current, real, and multifaceted menace.

These concerns led them to join the Students for Environmental Awareness in Medicine group, which approached the School’s curriculum leadership about including more about climate’s effects on health in students’ training.

Third-year medical student Madeleine Kline, who is also working on a PhD in infectious disease epidemiology at the Harvard T.H. Chan School of Public Health, recalled taking a class where students explored a case in which a patient’s asthma was clearly exacerbated by pollution coming from a major roadway near the patient’s home.

“We were talking about the pathophysiology of asthma. And I just felt like there was so much opportunity to talk about more — what causes the air pollution, why certain people are exposed to more air pollution than others, how air pollution is generated and by what system, how it affects the lung in different ways, and how we counsel patients about what to do about it,” Kline said.

Kline said the World Health Organization and several hundred medical journals have cited climate change as the greatest threat to global public health.

Many physicians and health care leaders agree on that score, but, she said, “That's just not represented in the way that we teach medicine, to both medical students and residents, in the way that we teach an understanding of the medical system, and the way that we prepare physicians for the challenges they're going to confront when they're actually practicing.”

Basu joined the students’ efforts as faculty chair of the HMS Climate Health Curriculum Working Group, which he said includes roughly 14 faculty members across a range of specialties at HMS-affiliated hospitals. Both students and faculty have been working with HMS course directors to integrate more climate and health topics into a variety of courses.

Basu said climate change’s effect on health equity is a key concept that needs to be taught and understood.

“People are not impacted equally by climate change, and what's hard about it is that the wealthy countries disproportionately cause the problem,” Basu said. “Climate change is a manifestation of how we haven’t built things with health and equity in mind.”

In 2021, the students consulted with Bernard Chang, Peabody Society advisory dean and HMS professor of neurology, and other faculty members, for guidance on how to proceed.

“Climate change is one of the truly existential threats to human health in the short- and long-term future, and our responsibility as a medical school is to ensure that our graduates are prepared to tackle climate-related challenges in their future careers as practicing physicians,” said Chang.

“Our curriculum at HMS becomes stronger when we include content that directly addresses some of the societal and environmental issues facing our patients and communities. The idea is not to supplant anything we are currently teaching in medical school, but rather to enrich it,” he said.

Students and faculty approached various course directors about including more on climate in their classes, including one course where students were learning about malaria in a class on infectious diseases.

“We asked, ‘Would you consider putting in this extra text in the slide about malaria, on how land use changes and increased rates of drought and flood are going to change vector-borne illnesses, and how that impacts human health?’ And he was terrific. And we worked together to refine the content,” Basu said.

Learning focus areas

At its January 2023 meeting, the HMS Educational Policy and Curriculum Committee responded enthusiastically to a presentation by Basu and other faculty and students involved in this initiative by voting unanimously to add climate change and health as one of the priority societal themes of the HMS MD curriculum, so that it can be officially embedded into all four years of the curriculum and tracked with accountability.

To that end, the groups have worked to develop five learning areas of focus. One would define the pathophysiological mechanisms by which climate change, air pollution, and ecological degradation affect human health. A second area would apply the knowledge of climate effects on human health to the clinical care of patients, including prevention, diagnosis, risk reduction, and counseling.

A third area would involve analysis of the historical and structural causes of climate change, air pollution, and ecological degradation and describe the ways in which the climate crisis creates and exacerbates inequities. A fourth would illustrate how health care systems contribute to climate change and how health care delivery is vulnerable to climate-related events. A fifth would involve exploring how physicians and health institutions can be part of solutions.

“Our goal is that no matter what you care about within medicine, the curriculum teaches you that understanding how climate change impacts health makes you a better clinician. That you can develop a practice of understanding how climate change creates and compounds disease that impacts your patients,” said Basu.

“You know, if you're a cardiologist you can be thinking about the impacts of air pollution on your patients. If you're a pediatrician, what about the asthma attacks that children are having? As an OB/GYN, I’m seeing that heat can be associated with poor obstetrical outcomes,” he said.

“The truth is that our current patients, our future patients, are already having their lives impacted by climate change,” said Malits. “It is a disservice to them if we are unaware of how those health impacts occur and if we don’t know what we can do to help prevent them and adapt to them. It's a reality we already exist in that we have to face.”

The group’s first goal was for the Pathways curriculum to have climate content included in every first-year course up to the Principal Clinical Experience (PCE) year. The group has also met with the Health Sciences and Technology curriculum leaders and those responsible for the PCE and post-PCE curricula to begin incorporating climate content into those curricula as well.

Their hope is that with the School having now officially adopted climate change into its curriculum, these efforts will be sustainable into the future.

This initiative builds upon the pioneering work of Eric Chivian, who founded and directed the HMS Center for Health and the Global Environment, the first center at a medical school in the U.S. focusing on the human health dimensions of global environmental change. In 1997, the center began offering a course in climate change and health that was open to all Harvard students and was shared with medical and public health schools around the world.

Now known as the Center for Climate, Health, and the Global Environment based at the Harvard T.H. Chan School of Public Health, its mission to deliver solutions-based research and use education and outreach to shape climate action that improves the health of vulnerable populations continues today.

“It’s good to see this commitment that this will continue to happen, and be something that people think about, even beyond the time that we're here,” said Kline. “I think there's a broader movement across the country that this needs to happen, both in medical schools and in residency training.”

Basu said HMS students have demonstrated a real desire to learn how climate change is affecting human health and to contribute to positive change.

“I trust that if we have as a core commitment that, in order to take care of our patients, we need to mitigate the harms of climate change on their health, we'll find solutions. And I think that's where doctors could play such a valuable role,” he said.