ORLANDO — It’s important for pediatricians not only to understand the causes and effects of climate change but also to know how to discuss this issue with families and make risk-based adjustments to their clinical practice based on the individual health and circumstances of each patient. That’s one of the key messages delivered at the annual meeting of the American Academy of Pediatrics (AAP) by Elizabeth C. Matsui, MD, MHS, professor of population health and pediatrics and director of the Center for Health and Environment Education and Research at the University of Texas at Austin Dell Medical School.
“Even though climate change has been here and has been affecting health already for a while, it’s just really impossible to ignore right now,” she told attendees in a session focused on climate change impacts on allergies and asthma. “The challenge is connecting the dots between something that is much larger, or feels much larger, than the patient and the family that’s in front of you.”
The reality, however, is that climate change is now impacting patients’ health on an individual level, and pediatricians have a responsibility to understand how that’s happening and to help their families prepare for it.
“From the perspective of someone who went into medicine to practice and take care of the individual patient, I think it has been more difficult to connect those dots, and for the people in this room, it’s our job to connect those dots,” Matsui said. She also acknowledged that many of the solutions are frustratingly limited to the policy level and challenging to implement, “but it doesn’t mean that we can’t make a difference for the patients who are in front of us.”
Charles Moon, MD, a pediatrician and Pediatric Environmental Health Fellow at the Children’s Environmental Health Center, Icahn School of Medicine at Mount Sinai, New York City, found the talk particularly helpful in providing information about both the broader issue and what it means on a local practice level.
“The biggest takeaway is that more people and more pediatricians are tuning in to this issue and realizing the dangers,” Moon said. “It’s clear that a larger community is forming around this, and I think we are at the cusp where more and more people will be coming in. We are really focusing on taking all the data and trying to figure out solutions. I think the solutions orientation is the most important part.”
Understanding the Big Picture
Matsui opened with a general discussion of the human causes of climate change and the effects on a global scale presently and in the future. For example, over the past 800,000 years, carbon dioxide levels have never been above 300 ppm, but they surpassed that threshold in 1911 and have reached 420 ppm today. The trapping of heat in Earth’s atmosphere caused by the increase in carbon dioxide and other greenhouse gases is leading to multiple phenomena that impact health, such as longer growing seasons; increased droughts, heat waves, and wildfire seasons; and higher temperatures. These changes, in turn, affect allergens and asthma.
, Matsui said. Childhood is a critical period for lung and immune development, and the Environmental Protection Agency’s 2023 Climate Change and Children’s Health and Well-Being report projects that an increase of 2° C in global warming will result in an additional 34,500 pediatric asthma cases and 228,000 allergic rhinitis cases per year, driven largely by predicted increases in ozone and 2.5-µm particulate matter. The report also forecasts an increase in 6240 asthma emergency department visits and 332 additional respiratory hospitalizations per year.
“We know that these associations that we see between climate change exposures and poor respiratory health outcomes in kids are biologically plausible,” Matsui said. “They’re not just correlation without causation. A lot of the mechanisms for how air pollution, allergies, and other factors directly affect the lungs of the airway epithelium have been worked out.”
An Increase in Allergens and Viral Infections
Pediatricians should prepare for anticipated growth in allergens and viral infections. The longer growing seasons mean that pollen seasons will also lengthen. Meanwhile, higher concentrations of carbon dioxide cause individual plants to produce more pollen.
“As the winters get warmer, mice that might not be able to survive during the winter are surviving, and mice reproduce at a very rapid rate,” she said. “The increase in moisture means that dust mites, which absorb their water — they drink by absorbing humidity that’s in the air — will be present in higher concentrations, and their range will expand.”
Fungal and mold exposures are also increasing, not just outdoors but also indoors, “and there are all sorts of allergic and respiratory health consequences of fungal exposure,” Matsui said. As hurricanes and flooding increase, storm damage can also make indoor environments more conducive to fungal and mold growth.
Extreme weather from climate change also affects infrastructure. “When there’s healthcare infrastructure disruption and other infrastructure disruption, it adds to the challenge,” she said. “It compounds all the other threat to health from climate change, so this overall problem of climate change and health is multidimensional and very complicated.”
Then there’s the impact of climate change on respiratory viruses, which are a major driver of asthma exacerbations, Matsui said. The greater variability in daytime temperatures affects environmental reservoirs, transmission patterns, geographical ranges, and seasonality of various respiratory pathogens. The prevalence of respiratory syncytial virus infections, for example, increases during humid periods.
“This is coupled with the fact that the projected increases in air pollution increase susceptibility to respiratory virus infections,” Matsui said. “In fact, climate change and air pollution are inextricably linked.”
Climate Change and Air Pollution
Climate disruption creates extreme weather patterns that then lead to worsening air quality due to high temperatures; heavier precipitation; and more forest fires, droughts, dust storms, thunderstorms, hurricanes, stagnation events, and other extreme weather. Matsui shared a map showing the substantial increase in days with stagnant air since 1973. During stagnation events, air pollution builds up in the atmosphere because of a stable air mass that remains over a region for several days, with low-level winds and no precipitation.
The pollutants can then contribute to rising temperatures. Black carbon particulate matter released from the burning of forests and other biomass absorbs more solar radiation, further contributing to temperature increases. Data from the National Bureau of Economic Research has shown that the US made big strides in reducing air pollution from 2009 through 2016, but it began to reverse in 2016 as severe weather events picked up.
Pediatricians need to be cognizant of the synergistic effect of these different impacts as well. “We oftentimes talk about these problems in a silo, so we may talk about air pollution and health effects, or allergens and health effects, or heat and health effects, but all of these interact with each other and further compound the health effects,” compared to just one of them in isolation, Matsui said.
For example, air pollution increases sensitivity to allergen exposure and increases reaction severity, which disrupts the immune tolerance to allergens. “Heat and air pollution also interact, and the combination of the two is more deadly than either one alone,” she said.
Air pollution from wildfire smoke is also more toxic to the lungs than air pollution from other sources, so if there’s wildfire-based air pollution, the impact on respiratory hospitalizations is significantly greater. Even in places that would not otherwise be at risk for wildfires, the threat remains of air pollution from more distant fires, as New York City experienced from Canadian wildfires last year.
“This is a problem that is not just isolated to the parts of the world where the wildfires are located,” Matsui said.
Moon, who practices in New York City, said he really appreciated Matsui’s perspectives and nuanced advice as a subspecialist “because it’s obvious that the way we deliver healthcare is going to have to change based on climate change.” He hopes to see more subspecialists from other pediatric areas getting involved in looking at climate impacts and providing nuanced advice about changing clinical care similar to the examples Matsui provided.
Air pollution can also be deadly, as a landmark case in the United Kingdom revealed a few years ago when the court ruled that a child’s death from an asthma attack was directly due to air pollution. In addition to causing worse asthma symptoms and exacerbations, air pollution also adds to the risk of developing asthma and impedes lung growth, all of which disproportionately affects disadvantaged and minoritized communities, she said.
Greater Impact on Disadvantaged Populations
Matsui called attention to the equity implications of climate change impacts on health.
“If you have a community that does not have the infrastructure and access to resources, and that same community has a prevalence of asthma that is double that of their more advantaged and white counterparts, then the impacts of climate change are going to be amplified even more,” she said.
For example, a 2019 study found that the biggest predictor of the location of ragweed plants has to do with vacant lots and demolition of housing. Ragweed plants being more common in neighborhoods with vacant lots will disproportionately affect disadvantaged neighborhoods, she said. Another study found in Baltimore that mouse allergens — specifically urine — were a bigger cause of asthma in low-income children than were cockroach allergens.
“It’s important to consider context,” including age, gender and social and behavioral context, she said. “We as pediatricians know that children are particularly vulnerable, and what happens to them has an effect across the lifespan.”
Furthermore, pediatricians are aware that disadvantaged and minoritized communities lack infrastructure; often live in areas with greater air pollution; often have heat islands in their communities without protection, such as tree canopy; and may be at greater flooding risk. “Poverty is also associated with increased vulnerability” because of poorer housing and infrastructure, less education, less access to care, more preexisting health conditions and greater discrimination, she said.