Longhorn Cattle at Knepp Wildland, 2019. Photo by Peter Eastern CC BY-SA 4.0
Anna Swedin | February 22, 2026
Trophic rewilding has the capacity to help stymie both accelerating climate change and species extinction. Ecosystem-shaping animals have the capacity to capture enormous amounts of carbon, furthering the goals set by the UN Framework Convention on Climate Change and intergovernmental biodiversity commitments.
Climate Change
Climate change has the potential to be the most serious threat to the stability of our world as we know it, and adaptive solutions will be necessary to buffer global communities against its ramifications: rising air temperatures, warming oceans, intensifying storms, melting Antarctic sea ice, and changing precipitation patterns among other hazards. The international consensus that the unprecedented rise in atmospheric carbon dioxide from fossil fuel combustion will wreak havoc on Earth’s climate if left unchecked has led world leaders to establish the United Nations Framework Convention on Climate Change (UNFCCC or Convention). One of the signature attributes of the Convention is that it places the onus on developed countries, which produced the lion’s share of past and current greenhouse gas (GHG) emissions, to lead the way toward climate adaptation and mitigation measures. Unfortunately, the United States has withdrawn from the UNFCCC, despite emitting the largest share of the cumulative climate pollution heating our planet’s atmosphere, while President Trump denounces clean energy.
Though the US has largely abdicated its role in promoting intergovernmental cooperation to address climate change, other countries have not been so reluctant to take action. Most significantly, the Paris Agreement has spurred the development of climate solutions intended to hold global mean temperature rise to 1.5 °C. Preventing the current warming trend from breaching this 1.5 °C threshold requires “negative emissions” solutions that remove and store 500 Gt of atmospheric CO₂ between now and 2100. This would require removal and storage of 6.5 Gt of CO₂ per year.. The current rate of CO₂ emissions is projected to overshoot our remaining carbon budget, but net-negative emissions can compensate for this carbon debt. Achieving net-negative emissions requires removing more CO₂ from the air than is emitted. While reducing greenhouse gas emissions is essential to meet this goal, the UN Secretary-General warned world leaders that “adaptation must not be the neglected half of the equation.” Adaptation methods include natural climate solutions such as afforestation, reforestation, and restoration. Forest cover produces woody biomass and mitigates atmospheric CO₂ pollution by sequestering and storing carbon over long timescales.
In recognition of the climate benefits of forests, the UNFCCC’s 19th Conference of the Parties (COP19), held in Warsaw, Poland, established the Warsaw Framework for REDD+ (reducing emissions from deforestation and forest degradation). Subsequently, the 2015 Paris Climate Agreement recognized REDD+ as a key process in Article 5, instructing participating countries to implement policies aimed at “enhancement of forest carbon stocks in developing countries, while reaffirming the importance of incentivizing, as appropriate, non-carbon benefits associated with such approaches.” Many tropical forest countries make specific reference to REDD+ whilst describing their strategy for reducing national emissions in their Intended Nationally Determined Contributions (INDCs). Also encouragingly, the most recent Convention, COP26, revisited climate pledges made under the 2015 Paris Agreement, and 137 countries committed to halt and reverse forest loss and land degradation by 2030. The countries who have signed the pledge cover around 85% of the world’s forests.
Biodiversity Loss
Anthropocentric impacts on the planet aren’t limited to the atmosphere. Another striking feature of human-induced environmental change is the decline in abundance and geographic range of wild animals, which places various species at risk of extirpation or extinction. Biodiversity loss is largely a result of habitat loss and degradation, overexploitation, eutrophication, exotic species proliferation, and climate change, as well as the interactions between these drivers, and the resulting cascading effects of trophic webs. Calculations at the time of the 1992 Convention on Biological Diversity (CBD) found that the rate of extinction was potentially 10,000 times the natural rate, a trend which has done nothing if not increased in the intervening years. Beyond aesthetic and moral justifications for preserving the diversity of animal species, so-called “keystone species” possess instrumental value by performing unique and irreplaceable roles in the natural environment and thereby maintaining the health of ecosystems and the biosphere.
In 1980, and subsequently in 1991, the International Union for Conservation of Nature and Natural Resources (IUCN), United Nations Environment Programme (UNEP), and World Wildlife Fund (WWF) formulated a comprehensive plan for preserving biodiversity in their World Conservation Strategy (WCS), which set the foundation for the biodiversity concept in international law. More recently, the 2019 UN Climate Action Summit, IPCC Sixth Assessment Report, and Convention on Biological Diversity Post-2020 Global Biodiversity Framework (Framework) have shifted towards recognizing the importance of an integrated approach, where natural climate solutions enhance species conservation. Indeed, the Framework states that biodiversity loss, climate change, and ecosystem health are “interrelated and mutually reinforcing, so these environmental crises need to be addressed in an integrated, comprehensive, holistic and urgent manner.” Moreover, the “30 by 30” initiative, set by the Kunming-Montreal Global Biodiversity Framework at COP15, aims to conserve 30% of global land and sea areas. Further progress was made with the adoption by UN Member States of the legally-binding Biodiversity Beyond National Jurisdiction (BBNJ) Agreement, also known as the “High Seas Treaty,” in 2023. The BBNJ Agreement strengthens the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction.
Trophic Rewilding
Increasing evidence suggests that biodiversity loss and climate change are highly intertwined, and “trophic rewilding to animate the carbon cycle” (TRACC) has the potential to serve both aims of climate mitigation and biodiversity conservation simultaneously. Most natural climate solutions focus on protecting and restoring plants (primarily trees, mangroves, and seagrasses) because the assumption that animals contribute little to ecosystem functioning, and the difficulty in modeling animal effects at global scales, has resulted in limited investigation into animals’ role in biogeochemical cycling. However, Yale researcher Oswald Schmitz has found that wildlife conservation can be used explicitly to enhance carbon capture and storage, a concept he termed “animating the carbon cycle” (ACC). ACC relies on “trophic cascades,” the food-web interactions that drive biogeochemical processes, as well as “rewilding,” the restoration and protection of interconnected wilderness landscapes large enough to support wide-ranging mammals. Ultimately, trophic rewilding is premised on utilizing the ecosystem services of wild animals in the functional roles they play across landscapes and seascapes.
Trophic rewilding recognizes that animals, particularly large-bodied herbivores, have important effects on ecosystem carbon capture despite their smaller total biomass relative to other biological drivers of carbon cycling, such as plants or microbes. Though wild animals contain only 0.3% of the carbon held in the biomass globally, many animals nonetheless exert an outsized influence on the amounts of carbon in plants, soils, and sediments relative to the conditions in which they are absent. A diversity of medium-to-large-bodied animal species with various functional roles allow for foraging and movements that redistribute seeds and nutrients across landscapes, as well as trampling, burrowing, wallowing, and ecosystem engineering, which cause soil and sediment disturbance. Seed dispersal supports the germination of large-seeded trees with carbon-dense wood, while herbivory reduces plant competition and enhances organic carbon storage in the soil—all ways that animals engage in carbon capture.
This phenomenon is happening in real-time in the Ţarcu mountains of Romania, where around 100 European bison were gradually reintroduced to the area, starting in 2014, after having been extirpated 200 years ago. Over 170 now graze over some 48 square kilometers. The bison’s domain has also become a “carbon hoover,” sucking an estimated 200,000 tons of carbon dioxide out of the atmosphere every year. The bison compact soil, disperse seeds, and create varied habitats through their browsing, all of which has turbocharged the environment’s ability to absorb carbon. The Țarcu grasslands are now capturing roughly 10 times as much carbon as they were before bison were reintroduced.
Schmitz has estimated that protecting and restoring nine types of animals (marine fish, baleen whales, sharks, gray wolves, wildebeest, sea otters, musk oxen, African forest elephants, and American bison) could lead to the capture of 6.4 billion tons of carbon dioxide annually, or 6.41 GtCO₂ yr⁻¹ of negative emissions––an amount approximately equal to the yearly emissions of the US. This could meet 64% of the current global natural climate solutions target of 10 GtCO₂ yr⁻¹, although some of this might be already accounted for by preserving these species’ habitats. Nevertheless, including animals in natural climate solutions could help shorten the timeframe over which 500 GtCO₂ is drawn out of the atmosphere.
Implementation
Despite its rhetoric of biodiversity co-benefits, the UNFCCC’s REDD+ framework fails to recognize the functional role of animals. I would posit that failure to address defaunation compromises the long-term viability of REDD+. Animals should be deliberately included in the design, monitoring, reporting, and verification procedures for carbon offsets. Alternative rules, regulations and implementation mechanisms such as no-take zones, quotas, and seasonal restrictions should be established amongst local hunters and resource users to avoid loss of animal diversity in order for REDD+ to adequately safeguard biodiversity.
Moreover, appropriately valuing carbon offsets produced by animals could change the policy narrative owing to the potential to attract significant, alternative revenue streams to finance conservation. United Nations COP26 and the 2025 IUCN World Conservation Congress highlighted the importance of financial market participation, and nature-based solutions that include the carbon services of wild animals have the potential to attract substantial investments, while also boasting interrelated socio-economic, and ecological advantages. Moreover, the rewilding framework may gain increased traction given the ambitious targets for expanded protected area networks being proposed. For instance, the Canadian government has endorsed the Convention on Biological Diversity goal of 30% protection by 2030, and Bhutan recently announced that it has achieved 50 percent protection by putting over 42% of its land in protected areas and over 8% in biological corridors.
Biodiversity and climate operate in tandem and are functionally interdependent: reestablishing animal species to ecologically meaningful densities can “animate the carbon cycle” by enhancing carbon capture and storage. Animals play a critical role in dispersing seeds and enhancing the productivity of carbon-rich tree species, and many animal species are declining just as we are realizing how much they impact carbon capture and storage. Simultaneously meeting the UNFCCC, Convention on Biological Diversity, and other intergovernmental biodiversity goals requires innovative solutions that can be implemented over vast spatial scales. TRACC is one such solution. To ignore animals is a missed opportunity to hold climate warming within 1.5 °C.