As the world continues to weather the COVID-19 pandemic, it is incumbent on humanity to learn what we can from this historic challenge. The spotlight has been cast upon topics ranging from the role of healthy lifestyles to the durability of our medical system. However, there is a deeper lesson to COVID-19 that may hold humanity’s key to avoiding history or dooming us to repeat it. This lesson calls attention to the insidious connection between deforestation and infectious disease, and it calls upon physicians to combat deforestation as a matter of public health.

Many people correctly understand forests as guardians against global warming, but we must also understand them as guardians against infectious disease as well. By 2015, the World Health Organization (WHO) had already identified deforestation as the leading driver of new disease emergence among humans.1 The U.S. Agency for International Development further estimated that nearly 75% of new, emerging, or re-emerging diseases affecting humans over the past 20 years are zoonotic2—this includes human immunodeficiency virus (HIV), severe acute respiratory syndrome (SARS), Ebola, avian flu, influenza subtypes H5N1 and H1N1, and now COVID-19.

At its core, deforestation portends an increased risk of unleashing zoonotic illnesses. Animals that may harbor novel illness are forced to interface with humans as we either invade their habitats or force them to venture into our communities as we destroy their habitable space. Tragically, humanity’s hunger for land and lumber has spurred deforestation at a rate of approximately 12 million hectares of forest every year.3 (As a point of reference, one hectare is roughly equivalent to two football fields.)

The long-term prognosis of many large forests is even more grim when considering the growing role of forest fires. As trees are burned industrially or naturally, carbon dioxide is liberated and drives global warming.4 The warmer climate then spurs drought which primes swaths of forest to burn and release more carbon dioxide in turn. The gravity of this positive feedback cycle cannot be more real as we consider the historic wildfires fought from California to Colorado last year alone.

And here of all places, amidst the synergy of a COVID-19 pandemic superimposed on the climate change crisis, we may find a unique opportunity. The importance of preserving forests is not a new notion. However, deforestation remains a global issue and society’s attention is all too distractable to its most recent problems. After recognizing the connection between deforestation and infectious disease, then COVID-19 may become our canary in the coal mine.

Tragically, forests have no lobby and no lawyer. As a “renewable” natural resource, there are also no market incentives to slow deforestation. And while green organizations have formed to advocate for nature, the persistence and scale of deforestation show just how outmatched those advocates may be. The onus of revitalizing forest advocacy then falls to us as stewards of public health.

Internal medicine doctors have the unique responsibility of appreciating the interaction between seemingly unrelated organ systems. Moreover, we are trained to understand the broader implications which a focal problem may portend. A societal correlate may very well be our inclination to recognize the global impact of a relatively focal problem such as deforestation.

Our profession has never been more entangled with the conversation of climate health as it should be at this moment. With COVID-19 as an inescapable example, we cannot deliver comprehensive preventative health without also addressing deforestation. We must integrate the importance of ecological security in the agenda of public health.

At a fundamental level, we must stand as physicians and acknowledge ecological advocacy as a professional responsibility. The advent of COVID-19 may serve as a mere sample of larger infectious challenges if such a responsibility is neglected. Even without discussing the psychological and wider ecological impacts of deforestation, we simply cannot disentangle the health of our patients from the health of our environment.

Each physician can make a profound impact on our respective communities. We are obligate leaders and are entrusted by our patients to make decisions to safeguard their health. As such, we should feel comfortable, if not obligated, to spread the concern for environmental health to others. From casual conversation to publishing in academic works, physicians should cultivate awareness and engagement in protecting forests and the environment. We should stand ready to support programs that recycle reusable products, responsibly resource materials, and encourage sustainable agriculture.

Lastly, we must not shy away from escalating our leadership to the state and federal levels to discuss legislative action. Across the country, there are already innovative actions being considered. In California, for example, the government is discussing AB-416 California Deforestation-Free Procurement Act this legislative session. If passed, this bill would make it illegal for companies to procure goods that were cultivated at the cost of deforestation.5 AB-416, and others like it, would be innovative measures, but they are restricted to the state level and must be coupled with more legislation across the country to maximize any impact. These legislative initiatives would normally seem outside of the practitioner’s scope. However, we must consider the environment’s impact on public health and testify in support of such measures. If meaningful change is to happen, we must guide and drive governmental action.

The COVID-19 crisis has proven itself an unprecedented disaster. It is crucial for physicians to understand not only the disease itself, but the relationship society holds with our environment that may be subjecting the entire globe to undue infectious risk. We must also recognize that the problem is expected to grow as global warming continues. Armed with this knowledge and the position of leadership, it is our duty to intervene upon the cultural and legislative dialogue. We have the responsibility to inform and advocate for programs that reuse materials, restore devastated spaces, and spare overtaxed resources for the sake of our patients and society at large. Ultimately, if we do not heed the warnings of recent zoonotic illnesses such as Ebola and COVID, then we resign ourselves to the next pandemic.


  1. Romanelli C, Cooper D, Campbell-Lendrum D, et al. Connecting Global Priorities: Biodiversity and Human Health. Geneva, Switzerland: World Health Organization (WHO); 2015, p 9.
  2. United States Agency for International Development. Emerging pandemic threats. Last updated May 24, 2016. Accessed May 15, 2021.
  3. UNFCCC. Forests as key climate solution. Published November 30, 2015. Accessed May 15, 2021.
  4. Jay A, Reidmiller DR, Avery CW, et al. Overview. In Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II. U.S. Global Change Research Program: Washington, DC; 2018, pp. 33-71. doi: 10.7930/NCA4.2018.CH1.
  5. California Legislative Information. AB-416: California Deforestation-Free Procurement Act: public works projects: wood and wood products. Annual, 2020-2021 Reg. Sess. (Cal. 2021).



Advocacy, COVID-19, Health Policy & Advocacy, Leadership, Administration, & Career Planning, SGIM, Social Determinants of Health

Author Descriptions

Dr. Balaban ( is a senior resident in the department of internal medicine at the University of Colorado School of Medicine and will attend fellowship through the University of Colorado’s Climate Change and Health Policy program starting 2021. Ms. Garimella ( is a fourth-year medical student at the University of Colorado School of Medicine. Dr. Sorensen ( is an Emergency Medicine physician at the University of Colorado School of Medicine and the Colorado School of Public Health.