Dec. 01 2021

Climate in Crisis

Public health challenges posed by climate change are already threatening populations worldwide. The School’s programs are training the next generation of leaders to fight back.

Kate Weinberger thought she had her academic career all figured out. It was 2009 and she was on her way to becoming an ecologist with a master’s degree from Columbia University’s Department of Earth and Environmental Sciences. Then an elective course, Public Health Impacts of Climate Change, offered through the Columbia Mailman School, inspired a new path.

The following year, she enrolled in the School’s newly launched Climate and Health Program, the first of its kind in a school of public health. Five years later, she became its first PhD recipient for a dissertation on how New York’s changing tree pollen levels affect allergic diseases such as asthma. (A warmer, wetter climate extends the pollen season for some species.)

After her graduation in 2015, Weinberger spoke at a White House summit on the health impacts of climate change. “I came late to public health,” she says. “But I took one course and was totally sold on the concept. There’s a real need for research on how climate change impacts health, which people and communities are going to be most affected, and how to protect health as temperatures continue to rise.”

Weinberger watched Columbia Mailman School’s Climate and Health Program grow from a small initiative in the Environmental Health Sciences Department into a multibranch initiative that has incubated a growing cadre of researchers doing cutting-edge, cross-disciplinary science, including Weinberger herself who is now an assistant professor at the University of British Columbia, where her research focuses on the health effects of extreme heat. Today, the Climate and Health Program is a schoolwide, interdisciplinary program that will serve as the health arm of the new Columbia Climate School. It partners with other Columbia institutions, including the Earth Institute, the International Research Institute for Climate and Society, and the NASA Goddard Institute for Space Studies. As the program has grown, it has expanded its work to found the Global Consortium on Climate and Health Education (GCCHE), which is leading health professions schools worldwide to train future leaders in climate-related issues.  

That need to connect the climate crisis and public health is at the heart of the Climate and Health Program. “It is critical that we—the public, scientists, government officials, corporations—view the effects of climate change through a public health lens,” says program director Jeffrey Shaman, PhD, professor of Environmental Health Sciences. “The fires, floods, extreme storm events, sea level rise, and rising temperatures we are witnessing are already profoundly affecting human health and well-being. We urgently need experts versed in these multidisciplinary issues who can effectively communicate their complexities to politicians, governments, corporations, and the public.” 

The United Nations Intergovernmental Panel on Climate Change warned earlier this year that “human-induced climate change is already affecting many weather and climate extremes in every region across the globe” and cited heat waves, heavy precipitation, droughts, and tropical cyclones as outcomes. The public health effects are layered and complex: Increased ozone air pollution results in 4.2 million premature deaths annually according to the World Health Organization (WHO). Outbreaks of infectious diseases like Zika, malaria, and dengue fever are emerging in new hot spots. Extreme and more frequent floods and rainstorms in some regions and droughts and wildfires in others are increasingly deadly. Food security will become a more significant issue as temperatures and carbon dioxide levels rise, leading to decreased protein in crops such as barley, rice, and wheat. Many of the negative effects fall disproportionately on poorer populations, older adults, and children, and they strain countries lacking the resources to address them.

Shaman points to the Lake Chad area in central Africa, where the population is among the poorest on the planet, as an example of the devastating impact of climate change on health, poverty, and political instability: Increasing temperatures and a 50-year drought dramatically reduced the lake’s size. The fishing industry turned to agriculture, which accelerated the drying of the lake. The resulting food and water insecurity has helped fuel the rise of Boko Haram and the Islamic State in the region, and nearly 10.6 million people, or half the population, now need humanitarian assistance, according to the United Nations, and more than 3 million people have been forced to flee their homes. Climate change is not the only driver of this crisis, Shaman says, but it is a significant part of the stressors that incite societal conflict and, ultimately, collapse. “How are we going to anticipate the next Lake Chad and deal with it while it’s happening?” he asks.

Cecilia Sorensen, MD, who joined as director of GCCHE in 2021, started becoming more aware of environmental impacts on health a decade ago, while in medical school at Drexel University. She was working in Cameroon, where she founded the Bush Medicine Partnership to bring healthcare to communities in need. A drought meant there was no food to sell, so people there didn’t have money to go into the city for healthcare. “Back then, I didn’t have any mentorship,” she says. “There wasn’t anybody who was even talking about climate change and desertification and how that impacts health and vulnerable populations.” Today, in her role leading GCCHE, Sorensen is in a position to help ensure that students around the world have mentors and that a culture of cross-disciplinary partnership builds to address this global crisis.

Sorensen also saw the effects of the climate crisis while working in a camp in Lebanon for Syrian refugees. A drought more severe than anyone could remember killed the majority of livestock and forced people into already crowded cities. “I started thinking, How can we provide education for health professionals to help in these situations?” says Sorensen, who has published papers on the climate crisis, the effects of heat and smoke, and the need to build resilience in low- and middle-income countries 

The widespread impact of climate change on human health was just beginning to be understood when the Columbia Mailman School Climate and Health Program launched. Ten years ago, examining the health effects of climbing temperatures was novel. Now, it’s clear that poor health and deaths result not only from heatstroke, but also from cardiovascular disease, respiratory disease, and cerebrovascular disease exacerbated by extreme heat resulting from climate change (and worsened by air pollution). And that is just one of the many ways that climate and health interact. In many regions, the effects are piling atop one another.

That’s why the School’s interdisciplinary approach is critical. “We cannot only look at one air pollutant or one weather variable at a time,” says Marianthi-Anna Kioumourtzoglou, ScD, an assistant professor at the School. Kioumourtzoglou is an environmental engineer and air pollution epidemiologist who uses computer modeling to examine how climate change drives air pollution and how that impacts health, including mental health. “We are beginning to increasingly understand there is a need to look at many things together,” she says. “It’s not just air pollution and temperature, but also snowstorms and hurricanes and coastal storms and flooding. Some are becoming more intense. Some are becoming more frequent. We are exposed to all of these together and we need to understand how this changing system impacts human health.”

In the early years, research efforts in the Climate and Health Program were focused in areas like air pollution, infectious disease spread, and the effects of extreme heat. More recently, as the faculty and the student body have expanded, so has the research, which now includes food security, neurodevelopment, epigenetics, and mental health. Students and faculty often come to Columbia Mailman School interested in one subject and find their focus pulled in exciting new directions. Shaman notes that even seemingly unconnected issues, such as construction, urban development, and agricultural practices, can be viewed through the kaleidoscope that is climate and public health.

Sorensen sees GCCHE focusing on building a community of practice and creating trained experts to address interconnected issues. “A consortium is about getting people from different parts of the world together to develop solutions. In my experience in the climate and health world, we’re all siloed. So how can we open the lines of communication and start troubleshooting together?”

For Shaman, a leading expert on forecasting the spread of flu as well as on COVID-19, research is inherently interdisciplinary. His work draws on virology, epidemiology, infectious disease, mathematical modeling, statistics, and atmospheric science. He examines how meteorology affects human health, notably the seasonality, transmissibility, and survival rates of influenza, as well as the effects of heat and humidity exposure. “Many climate impact studies can only be achieved with an interdisciplinary lens,” he says. Drought, for example, affects crop yields and food insecurity, but also economic insecurity, forced migration, and conflict.

Kioumourtzoglou brings together a multitalented team of experts for her projects. She is looking at how short-term exposure to high temperatures affects heart attacks and the influence of neighborhood factors, like green space and building size, on both climate and health. Her team includes researchers expert in temperature prediction models and in the epidemiology of stroke and myocardial infarction, as well as biostatisticians and computer scientists. She also has published intriguing work demonstrating an association between long-term exposure to air pollution and the onset of depression. Using advanced modeling methods, her team was the first to show that prolonged exposure to fine particles in air pollution accelerates neurodegenerative conditions including dementia, Alzheimer’s disease, and Parkinson’s disease. 

Lewis Ziska, PhD, associate professor of Environmental Health Sciences, is a plant physiologist who studies the nexus of climate change, carbon dioxide, plant biology, and public health. Over decades, he has published studies reporting that climate change exacerbates allergy seasons, makes herbicides less effective, and could drive a decline in pollen important for bees. He has also delved into what strains of rice and wheat will be best suited for a changing climate. The rise of carbon dioxide in the atmosphere, he says, means plants may grow faster, but will be less nutritious. “What you are putting in your mouth, now and for the rest of the century, may be carbon-rich and nutrient-poor,” he writes. “And the consequences for human nutrition, and human health (not to mention plant ecology), are only now beginning to be examined.” 

The urgency of the Climate and Health Program’s mandate has a tendency to pull people in, and Darby Jack, PhD, associate professor of Environmental Health Sciences, is one of them. He came to Columbia to do postdoctoral research at the Earth Institute focusing on energy choices in developing countries. He soon found himself meeting with a group that included Columbia Mailman School scientists to discuss the health consequences of cook stoves that burn wood, which are a significant source of air pollution that leads to heart and lung disease in the developing world. Cook stoves emit greenhouse gases and black carbon. “Air pollution and climate change are interlocking problems,” he says. “There’s a growing sense that there is a real opportunity for a public health dual win if we can address both of these problems in the same framework.”

Underpinning much of the work at Columbia Mailman School are contributions from the Biostatistics Department. Kiros Berhane, PhD, its chair, likes to say his field “provides quantitative common sense to public health research and training.” He is leading a large, collaborative team on environmental biostatistics, with a focus on multiple outcomes, including synergistic effects of the environment with genetic and epigenetic factors. Berhane was the lead biostatistician of a 22-year-study that found children living in polluted communities close to motor vehicle traffic were more likely to suffer deficits in lung growth. He mines databases, but also collects primary data. (One emerging tool is data from satellites.) He uses machine learning to combine evidence from many sources. “You have to be able to extract the signal from the mountains of information,” says Berhane, who has just been awarded a grant as part of the Data Science Initiative for Africa. 

Columbia Mailman School’s Climate and Health Program is training academic researchers, but it is also helping to build a workforce to better understand climate and health and create solutions via policy, health systems, and care. Andrea Baccarelli, MD, PhD, the Leon Hess Professor and chair of the Department of Environmental Health Sciences, says all the talk about stopping climate change ignores the fact that it is here. “We need to find ways for people to live in a changing climate,” he says. “There is no way we can stop climate change anymore. We’ve already had a substantial change in climate that we have to cope with. We have a landmark program where, for the first time worldwide, we have started to study how climate impacts human health and how to make people resilient and adaptive to our changing planet.” 

Some graduates go on to teach. Others sign on with consulting firms, work for city or state governments, or join the Centers for Disease Control and Prevention or WHO. The number of MPH students seeking a certificate in the Climate and Health Program has increased steadily, and the program is averaging nine doctoral students per year. The Environmental Health Sciences Department has expanded as well in recent years, bringing on faculty with expertise in plant physiology, infectious diseases, and epidemiology, with a parallel growth in courses. Other schools are beginning to follow the Columbia Mailman School’s lead. The University of Miami and the London School of Tropical Medicine and Hygiene launched their versions in 2019.

Columbia Mailman School cemented its leadership role in climate and health in 2017 when it launched GCCHE, a global network of health professions schools and programs focused on training medical, nursing, and public health students, and others to prevent, reduce, and respond to the health impacts of climate change. Proposed and endorsed at the Paris Climate Accords, and then recommended as a key climate and health initiative by WHO, the consortium has more than 200 members in 30 countries and is growing. Schools pledge to educate tomorrow’s leaders on the health impacts of climate change, and GCCHE hosts a flourishing virtual town square, where educators exchange scientific and educational best practices. GCCHE tracks and shares innovative ways institutions are integrating climate and health content into their curricula and convening webinars to discuss strategies, challenges, and success stories. It has also developed a set of core competencies in climate and health education. 

Sorensen notes that the COVID-19 pandemic highlighted the holes in healthcare systems and revealed the inequalities of care. “It’s the same thing with climate change,” she adds. “Those who are vulnerable are going to become more vulnerable. And our health systems are not prepared to protect them.”


Jim Morrison’s Washington Post Magazine story on retreat from climate-endangered areas won the 2021 award for Excellence in Reporting from the American Society of Journalists and Authors.