Anna Chamberlin, Contributing Illustrator

From essential nutrient redistribution to carbon capture, wildlife and biodiversity play vital roles in protecting planetary health.

A study published last week in “Nature Climate Change,” led by Yale School of the Environment professor Oswald Schmitz, revealed that expanding wildlife restoration and conservation efforts, or “trophic rewilding,” could lead to the capture of an additional 6.41 billion tons of CO2 negative emissions each year. This is equivalent to 95 percent of the quantity specified in the Paris Agreement to limit global warming to 1.5°C above pre-industrial levels, slowing irreparable climate damage.

“Some people are saying that the way to get to net zero [emissions] is through geoengineering and technology to scrub CO2 from our atmosphere … but we already have nature doing that,” Schmitz said. “The salient argument is that let’s use this tried and true technology — nature — to our advantage.”

This research was the product of an international collaboration between Schmitz and co-authors from eight countries across North America, Europe and Africa. 

Specifically, the study highlighted the ecological roles of various large-bodied vertebrates, ranging from whales to wolves, in stimulating natural carbon capture and storage in a process known as “animating the carbon cycle.”

Their findings reveal that animals can increase plant and soil carbon retention by supporting microbial and chemical carbon processing through their movements and waste production. This can influence fire regimes and permafrost patterns in their ecosystems, promoting carbon uptake, as well as distributing seeds and nutrients across diverse ecosystems.

Schmitz proposed that trophic rewilding shows promise to overcome some of the shortcomings of current approaches to tackling the climate crisis, such as merely shifting to renewable energy sources. The “heat trapping” properties of the residual CO2 in the atmosphere renders such efforts inadequate when it comes to achieving the targets set forth by the Paris Agreement, according to Schmitz. In contrast, he explained, trophic rewilding can strengthen our capacity to achieve negative emissions, “which helps to suck up the bolus of CO2 sitting in the atmosphere that’s built up ever since the start of the Industrial Revolution.”

Schmitz also emphasized that developing solutions for improving biodiversity, climate health and human health should be “functionally interdependent,” rather than mutually exclusive. He points to the fact that expanding natural climate solutions to include biodiversity and wildlife protection could “co-benefit biodiversity conservation and … support human livelihoods and welfare.” 

He stressed that we must “change the current mindset” away from the perception that animal conservation and natural climate solutions are competing for finite spaces and resources, and towards a perspective that underscores the interconnected “human-nature coexistence.” 

“You have the UN Climate Change Conference in Egypt and the UN Biodiversity Convention in Montreal … who didn’t really talk to each other and are often competing for attention,” Schmitz said. “I think that there’s a lot of opportunities for synergizing these [agencies] together and emphasizing a functional interdependence on each other.”

Avery Naperala SPH ’23 and Nicole Smith SPH ’24, both in the Department of Environmental Health Sciences at the Yale School of Public Health, concurred with this. They suggested that biodiversity and climate change solutions are important not only for environmental health, but also population health. 

Naperala, who works for Fair Haven Community Health Care says that they have been “prescribing nature” as a health intervention for patients. According to Naperala, there is extensive scientific literature that substantiates the benefits of spending time outdoors, which can help bolster immune systems and increase attention spans in children.

Smith emphasized the importance of empowering communities in the fight against climate change, pointing out the vital role that Indigenous communities play in promoting planetary health solutions.

“We need to refer to Indigenous People as the experts in the field and incorporate them more in policy decisions,” said Smith. 

Schmitz went on to describe how integrating trophic rewilding in local communities can provide individuals with agency to join the battle against climate change. For instance, local farmers and agricultural sectors are particularly well-positioned for this call-to-action, since they own large plots of land that can be used to restore American bison and other large animals for the purpose of carbon sequestration, according to Schmitz. 

“You don’t want a grizzly bear roaming through a city, of course, but insects can do the same job in gardens … so you can transform your backyard to improve carbon uptake,” Schmitz said. “In doing so, everybody can do their little bit and if you add that up across the globe, you get really significant results on the climate,” he adds.

Looking forward, Schmitz said he believes that investing in biodiversity and climate health is crucial to sustaining planetary health. Restoring and rehabilitating landscapes and seascapes around the world promotes the longevity and wellbeing of both the environment and humanity, he emphasized. 

“In the long run, the payoff will be worth the effort because I think more and more people will reconnect with nature and feel like they’re part of it rather than separate from it … which will also benefit human health and welfare,” Schmitz said.

The Paris Agreement is an international treaty adopted by 196 Parties at the United Nations Climate Change Conference in 2016.