The Breath-taking Effects of Climate Change

Neil Osterweil

May 05, 2023

To see the harmful effects of climate change firsthand, you need look no farther than the nearest pulmonary clinic.

The causes and effects are unmistakable: pollen storms leading to allergy sufferers flooding into allergists' offices. Rising air pollution levels increasing risk for obstructive airway diseases, cardiopulmonary complications, and non-small cell lung cancer.  Melting snowpacks and atmospheric rivers inundating neighborhoods and leaving moldy debris and incipient fungal infections in their wake.

"The reason why we think climate change is going to change the type of disease patterns and the severity of illness that we see in patients with respiratory diseases is that it changes a lot of the environment as well as the exposures," said Bathmapriya Balakrishnan, BMedSci, BMBS, from the section of Pulmonary, Critical Care and Sleep Medicine in the Department of Medicine at West Virginia University in Morgantown.

"What we're going to see is not just new diseases, but also exacerbation of chronic diseases, things like asthma [and] COPD. And there's also concern that patients who are otherwise healthy, because they now have more exposures that are due to climate change, can then develop these diseases," she said in an interview with Medscape Medical News.

Balakrishnan is the lead author of a comprehensive, evidence-based review focused on the effects of climate change and air pollution across the spectrum of pulmonary disorders. The review is published online ahead of print in the journal Chest.

"As pulmonologists, understanding and improving awareness of the adverse effects of climate change and air pollution are crucial steps. To inform healthcare providers of evidence-based methods and improve patient counselling, further research regarding measures that limit exposure is needed.  Empowering patients with resources to monitor air quality and minimize exposure is a key preventative measure for decreasing morbidity and mortality while improving quality of  life," Balakrishnan and colleagues write.

Similarly, in a statement on the effects of climate change on respiratory health, the American Public Health Association succinctly summarized the problem:

"Warmer temperatures lead to an increase in pollutants and allergens. Poor air quality leads to reduced lung function, increased risk of asthma complications, heart attacks, heart failure, and death. Air pollution and allergens are the main exposures affecting lung and heart health in this changing climate," the statement says.

Early Spring

Stanley Fineman, MD, MBA, a past president of the American College of Allergy, Asthma & Immunology and an allergist in private practice in Atlanta, Georgia, has seen firsthand how global warming and an earlier start to spring allergy season is affecting his patients.

"The season, at least in our area metro Atlanta, started earlier and has been lasting longer. The pollen counts are very high," he told Medscape Medical News.

"In February we started seeing pollen counts over 1000 [grams per cubic meter], which is unheard of, and in March about half the days we counted levels that were over 1000, which is also unheard of. In April it was over 1000 almost half the days."

Fineman and colleagues both in Atlanta and across the country have reported sharp increases in the proportion of new adult patients, and in existing patients who have experienced exacerbation of previously mild disease.

"Probably, what's happened is that they may have had some allergic sensitivity that resulted in milder manifestations, but this year they're getting major manifestations," Fineman said.

In a 2014 article in the journal European Respiratory Review, Gennaro D'Amato, MD, from High Speciality Hospital Antonio Cardarelli in Naples, Italy, and colleagues outlined the main effects of climate on pollen levels:

"1) an increase in plant growth and faster plant growth; 2) an increase in the amount of pollen produced by each plant; 3) an increase in the amount of allergenic proteins contained in pollen; 4) an increase in the start time of plant growth and, therefore, the start of pollen production; 5) an earlier and longer pollen season; 6) change in the geospatial distribution of pollen, i.e. plant ranges and long-distance atmospheric transport moving polewards," they write.

Bad Air

In addition to pollen, the ambient air in many places is increasingly becoming saturated with bioallergenic proteins such as bacteria, viruses, animal dander, insects, molds, and plant species, Balakrishnan and colleagues noted, adding that "atmospheric levels of carbon dioxide have also been found to increase pollen productivity. These changes result in greater over-the-counter medication use, emergency department (ED) visits, and outpatient visits for respiratory illnesses."

The rash of violent storms that has washed over much of the US in recent months is also likely to increase the incidence of so-called "thunderstorm asthma," caused when large quantities of respirable particulate matter are released before or during a thunderstorm.

Air pollution from the burning of carbon-based fuels and from wildfires sparked by hotter and drier conditions increase airborne particulate matter that can seriously exacerbate asthma, COPD, and other obstructive airway conditions.

In addition, as previously reported by Medscape, exposure to particulate matter has been implicated as a possible cause of non-small cell lung cancer in persons who have never smoked.

Critical Care Challenges

Among the myriad other effects of climate change postulated in evidence enumerated by Balakrishnan and colleagues are chest infections and pleural diseases, such as aspergillosis infections that occur after catastrophic flooding; increased incidence of Mycobacterium avium complex infections and hypersensitivity pneumonitis;  increased demands on critical care specialists from natural disasters, pollution-induced cardiac arrest; and heat prostration and heat stroke from increasingly prevalent heat waves.

The reviewers also examined evidence suggesting links between climate change and pulmonary hypertension, interstitial lung disease, sleep disorders, and occupational pulmonary disorders.

Power to the Patients

"Pulmonologists should counsel patients on ways to minimize outdoor and indoor pollution, using tight-fitting respirators and home air-purifying systems without encroaching on patients' beliefs and choices," the authors advise.

"Empowering patients with resources to monitor air quality daily, in inclement weather, and during disasters would help minimize exposure and thus improve overall health. The pulmonologist can play an important role in emphasizing the impact of climate change on pulmonary disorders during patient care encounters," they write.

Balakrishan tells Medscape that another important mitigation measure that can be taken today is education.

"In medical school we don't really learn about the impact of climate change; at least in my generation of physicians, climate change or global warming weren't part of the medical curriculum, but now I think that there's a lot of advocacy work being done by medical students who actually want more education on climate change and its effects on pulmonary diseases," she said.

The study by Balakrishnan and colleagues was unfunded. Balakrishnan reports no relevant financial relationships. Co-author Mary-Beth Scholand, MD, has received personal fees from serving on advisory boards and speakers bureaus for Genentech, Boehringer Ingelheim, Veracyte, and United Therapeutics. Co-author Sean Callahan, MD, has received personal fees for serving on advisory boards for Gilead and Boehringer Ingelheim. Fineman reports no relevant financial relationships.

CHEST. Published online April 10, 2023. Full text

Neil Osterweil, an award-winning medical journalist, is a long-standing and frequent contributor to Medscape.

For more news, follow Medscape on Facebook, Twitter, Instagram, YouTube, and LinkedIn


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.