Why stopping deforestation must be a priority for public health

If you care about preventing pandemics, it’s time to start caring about saving trees.

Almost all new infectious diseases, from HIV to Ebola to probably also COVID-19, emerge when a microbe “spills over” from animals to humans. Land-use change, particularly the clearing and degradation of tropical forests, is the largest driver of these spillovers, bringing wildlife into contact with domestic animals and humans.

The benefits of halting deforestation extend beyond slowing the emergence of infectious diseases. Tropical forests are critical for addressing climate change, perhaps the greatest public health threat we face, because they absorb vast quantities of carbon. They also contain two-thirds of the world’s diversity of life, despite covering less than 10 percent of the planet, and this biodiversity is crucial for human wellbeing.

Nevertheless, we have rarely ever observed deforestation discussed in the many meetings we have attended about global health security, the umbrella term used for pandemic prevention, preparedness and response. When we have brought it up, public health experts consistently deflect responsibility for tropical forests to those working on climate change or biodiversity. This is short-sighted.

With rates of forest loss higher now than they were earlier this century, it’s time to finally declare deforestation as the public health crisis that it is. Doing so could unlock desperately needed funds and increase the chances that recent commitments to save tropical forests move from mere words to action.

Why do public health leaders overlook the destruction of nature? We suspect there are two reasons.

First, traditional academic disciplines constrain thinking around complex issues such as infectious disease emergence. While epidemiologists increasingly embrace interdisciplinary public health approaches such as “One Health,” public announcements in support of these approaches often lack details on how to achieve desired outcomes or, when they include them, focus on what to do after a pathogen has already spilled over into humans rather than preventing spillovers in the first place. 

Second, public health leaders in government often focus on short-term victories that mirror political timelines rather than long-term efforts with impacts that are more difficult to quantify. It’s harder to prove the public health benefits of protecting the Amazon rainforest over a decade than it is to build diagnostic laboratories or administer vaccines.

Case in point is the Biden administration’s recently released pandemic strategy, which acknowledges the problem of spillover from habitat destruction but includes no measures to reverse it. Meanwhile, the strategy contains a goal to prevent laboratory accidents, which certainly merits investment but poses a lower risk of igniting a future pandemic than spillover from wildlife. This imbalance reflects a bias toward activities that are easy to measure and explain publicly over activities that are preventive.

The increased frequency with which novel pathogens are emerging demands that funders, from high-income countries to philanthropists, take a more holistic approach to preventing, rather than simply managing, pandemics. 

First, wealthy nations must financially support tropical countries in protecting forests such as through expanding protected areas, bolstering law enforcement and paying farmers to not clear forest. The recent $12 billion commitment to help over 100 countries end deforestation by the end of this decade is a great start. However, public health outcomes should be incorporated to help close the loopholes that led to failure from similar pledges in the past. Efforts are also underway by the Biden administration (for which there is bipartisan support in Congress) to establish a novel global fund to prevent and prepare for pandemics; it is imperative that upstream prevention of spillover through protection of tropical forests be incorporated within the fund. 

Second, the negotiators meeting on Nov. 29 to discuss a possible new World Health Organization agreement on pandemic preparedness and response must move from abstract statements in support of One Health to concrete actions. They should specifically outline mechanisms to implement activities needed to prevent pathogen spillover so that outbreaks can be prevented before they start, which is the most equitable approach to pandemic prevention.

Third, G20 leadership must include environmental and agriculture ministers in the new Global Health Threats Board that it is likely to create to improve global health security governance. The initial proposal limited membership to just health and finance ministers. Excluding the sectors that have most control over upstream preventive solutions to infectious disease threats will preclude a successful outcome.

Fourth, philanthropists must recognize that environmental conservation and public health are two sides of the same coin, rather than pitting the two against each other by funding one but not the other. For example, Bill Gates has three publications in the New England Journal of Medicine, the world’s leading medical journal, in which he shares his thoughts on how to address epidemics and pandemics. Not a single one addresses upstream prevention of spillover such as by stopping deforestation — including the latest one written during the current pandemic that calls for “keep[ing] it from happening again.” Many billionaire philanthropists amassed their wealth through disrupting businesses; they should harness their prowess for innovation to advance intersectional solutions for conservation and public health, which have for too long been considered distinct from each other.

There are currently no international funds allocated for the conservation of tropical forests to prevent pandemics before they start. Amid disease outbreaks, climate change and biodiversity loss, decision-makers must start prioritizing the protection of trees to protect human lives.

Neil M. Vora, MD, is a fellow with Conservation International where he leads its efforts on pandemic prevention. He served for nearly a decade with the U.S. Centers for Disease Control and Prevention (CDC), where he focused on outbreak response to viruses that originate from animals.

Jay K. Varma, MD,  is a professor of population health sciences at Weill Cornell Medical College. He served for 20 years with the U.S. Centers for Disease Control and Prevention (CDC) working on infectious diseases in Atlanta, Bangkok, Beijing, Addis Ababa and New York City.