Schools picking up the content are still in the minority. It can be hard to fit into an already-packed curriculum, and faculty at many schools still lack expertise in the topic, say some educators. But advocates of climate-change education say health-care providers must be trained to prevent, detect and treat conditions that may rise or emerge in new places as the climate changes.

“This is really the greatest health danger of our century,” said Mona Sarfaty, the director of the Medical Society Consortium on Climate and Health, a coalition of medical associations that represents roughly 600,000 doctors. “We must respond and make sure our health professionals are sufficiently educated.”

Last year was the fourth-warmest on record, according to the National Aeronautics and Space Administration and the National Oceanic and Atmospheric Administration, and the five hottest years have all occurred since 2014.

Increased temperatures, extreme weather events and air pollution tied to climate change take a toll on human health, physicians say. Hot weather can lead to illness and deaths from conditions such as heat stroke. Health professionals say they are seeing more severe allergies, respiratory illnesses and cardiovascular conditions due to increased air pollution and wildfires. Cases of infectious diseases like Lyme disease are also rising in some areas, as ticks, fleas and mosquitoes expand into new territory or take advantage of warmer winters.

These and other hazards including mental-health problems and food insecurity will worsen in the future, experts say.

So far, climate-related content is largely limited to electives and lectures, and hasn’t been flagged as a topic in core curriculum, according to a study of the national medical-school-curriculum database published late 2018 in the journal Academic Medicine.

“With limited curricular time and with many basic science and clinical science matters that need to be covered during the formative years of medical school, our educators must choose between topics that are more fundamental over others,” said a statement from the NYU School of Medicine and the NYU Long Island School of Medicine, which doesn’t have widespread coursework on climate change.

But 187 schools and programs have joined a two-year-old coalition launched by Columbia University’s Mailman School of Public Health that supports including climate change in health education. The Global Consortium on Climate and Health Education offers resources including links to slides, videos and online courses, as well as curriculum suggestions.

The AMA adopted its policy to support teaching on climate change to all physicians and medical students this June, and the International Federation of Medical Students’ Associations wants medical schools to add the topic by next year.

“Even in the past month, I’ve felt more of an exponential growth,” said Sheri Weiser, a professor of medicine at the University of California San Francisco, who has helped lead the movement to add climate-change education there.

UCSF has elective courses on climate and health and has worked to weave the content throughout the curriculum. One course, offered through the department of obstetrics and gynecology, discusses environmental exposures and women’s health. Other classes discuss sustainability and the carbon footprint of the health-care system.

At New York’s Icahn School of Medicine at Mount Sinai, a faculty-led initiative gets students involved in developing coursework. Christian Cayon spent the summer after his first year looking for spots in the curriculum where climate change could fit, such as asthma or heat illness. Mr. Cayon says he helped get a medical microbiology course to add content, including the connection between climate change and increasing tick-borne diseases. The Climate Change Curriculum Infusion Project has since added content to four additional courses.

The push for climate-change education is also focusing on health-care providers already in practice. Professional meetings for specialists including psychiatrists, dermatologists and pediatricians have included sessions and committees discussing the issue. The Yale School of Medicine offers a continuing medical education certificate in climate change and health, and the University of Colorado Department of Emergency Medicine now offers a fellowship for physicians on climate change and health policy.