Photo detail / credit: Bengal Tiger, Sanctuary Photolibrary, Sanctuary Asia Magazine – Siddannavar Praveen
Rigorous scientific research shows that bringing wildlife populations back is a
cost-efficient, rapid, and scalable solution
for both climate and biodiversity crises, rivalling top IPCC mitigation measures.
Photo detail / credit: Grey wolf, Finland – Grégoire Dubois
WHY ACC MATTERS
The Animating the Carbon Cycle (ACC) model represents a groundbreaking approach that underscores the crucial, yet often overlooked, role of wild animals in boosting CO2 capture and storage within ecosystems.
Technological solutions alone are not enough and reaching net zero emissions won’t curtail the climate crisis on its own. We still need to remove legacy carbon dioxide accumulated since the Industrial Revolution to avoid a 1.5°C – 2°C temperature rise to solve the climate crisis.
The best place to store excess CO2 is in soils and sediments of the land and ocean but we’ve been undervaluing the role animals play in controlling the carbon cycle. Rooted in rigorous scientific evidence, ACC highlights that protecting and restoring wild animals and their functional roles can enhance natural carbon capture and storage to help humanity meet the target of halving its greenhouse gas emissions by 2030.
“We must not see ACC as another offset, ACC must be seen as an approach that can have a meaningful impact on enhancing the carbon sinks.”
Professor Oswald Schmitz, Yale University
A DATA-DRIVEN & PEER-REVIEWED MODEL
The Yale School of the Environment and the Global Rewilding Alliance have developed the Animating the Carbon Cycle (Yale/GRA ACC) model to measure and enhance the climate benefits of rewilding. This model aims to inform and drive global conservation efforts and investments.
Explore the peer-reviewed science that supports this approach:
TROPHIC REWILDING CAN EXPAND NATURAL CLIMATE SOLUTIONS
Published on March 27, 2023, in Nature Climate Change, this pivotal study was written by 15 scientists from 8 countries representing 13 highly accredited academic institutions and 3 conversation organisations with a global outreach. It reveals that rewilding key wildlife species could not only help reduce emissions but also play a crucial role in drawing down vast amounts of legacy carbon dioxide, making it a major policy option.
Highlights include:
- Protecting populations of species like marine fish, wildebeest, and sea otters could secure 5.8 Gt CO2 per year, resulting in 440 Gt CO2 captured by end of century.
- Restoring species such as American bison, African forest elephant and baleen whales could capture an additional 0.6 Gt CO2 annually, or 40 GtCO2 by 2100.
- Protecting and restoring additional species could contribute significantly to removing 500 Gt CO2 by 2100.
According to Nature Climate Change’s article metrics, our Trophic Rewilding article has been:
- Accessed over 15k times
- Referenced in 119 news outlets
- Tweeted 1052 times
Overall, the article is in the 99th percentile (ranked 258th) of the 432,599 tracked articles of a similar age in all journals and the 95th percentile (ranked 3rd) of the 73 tracked articles of a similar age in Nature Climate Change
In addition, our research published in Nature Climate Change very quickly became one of the
top 5% most impactful scientific papers on Altmetric ¹
ANIMATING THE CARBON CYCLE: How Wildlife Conservation Can Be a Key to Mitigate Climate Change
This study explores how animals influence carbon dynamics directly and indirectly, enhancing ecosystem CO2 capture and storage. It highlights the crucial role of wildlife in accelerating nutrient recycling and the importance of their conservation, and looks beyond the nine species of the previous paper and emphasises the need to put ACC into human context.
CONTEXT MATTERS WHEN REWILDING FOR CLIMATE CHANGE
Trophic rewilding is complex and the impact of a species on the carbon balance of an ecosystem is context dependent. In some cases animals increase CO2 storage, while in others they may have no impact or even reduce CO2 storage. Further, sometimes, the goals of biodiversity conservation, climate change mitigation, and human welfare do not align perfectly. Successful outcomes require practitioners to exercise cautious consideration of local factors, an upholding of ethical principles in these efforts, and use technology to track progress.
REWIRING THE CARBON CYCLE: A Theoretical Framework for Animal‐Driven Ecosystem Carbon Sequestration
This paper provides the theoretical and mathematical background of the Yale/GRA Carbon Capture Framework Model.
ACC IN THE NEWS
Our research has been published in 70 mainstream outlets, 50 countries and translated in 12 languages
IF YOU ARE A SCIENTIST YOU CAN SUPPORT THIS PIONEERING RESEARCH
Photo detail / credit: Lion Tamarin – AMAP Brazil
THE KEY ROLE OF WILD ANIMALS
Wild species perform several general functions that impact ecosystem processes and ultimately help to capture carbon in plants, soils, and sediments in a most remarkable way.
FORAGING
Wild animals consume vegetation and other organisms as part of their diet, altering plant communities and controlling the abundance of various species. This activity regulates the carbon cycle by limiting plant growth in some areas while promoting growth in others, indirectly influencing carbon sequestration.
DISTURBANCE
Wildlife-induced disturbance involves the physical alteration of ecosystems, such as trampling, digging, or knocking over trees. These disturbances can shape plant and soil structures, creating opportunities for new growth, which often supports increased carbon capture by promoting the growth of carbon-dense species.
SEED DISPERSAL
Many animals contribute to carbon cycling by dispersing seeds over wide areas, facilitating the spread of plants, particularly carbon-sequestering trees and vegetation. This enhances plant diversity and forest regeneration, helping ecosystems store more carbon in both plants and soils.
NUTRIENT DEPOSITION
Through defecation and other waste products, wild animals deposit nutrients in ecosystems, enriching soils and promoting plant growth. Nutrient deposition supports more productive ecosystems, which in turn sequester greater amounts of carbon in plant biomass and soils.
ORGANIC CARBON DEPOSITION
Wild animals contribute organic matter such as leaves, bones, or carcasses to the environment. This organic material becomes incorporated into soils and sediments, where it can be stored for long periods, locking away carbon and reducing its release into the atmosphere.
These functions collectively influence the carbon cycle, helping ecosystems either protect existing carbon stores or enhance their capacity to capture and store more carbon.
Pathways identified and explained in
ANIMATING THE CARBON CYCLE: How Wildlife Conservation Can Be a Key to Mitigate Climate Change
The multiple pathways by which wildlife can control the carbon cycle by mediating (bowties) exchanges (arrows) of energy (solar radiation) and carbon (CO2) between the atmosphere and different ecosystem types on land and in the ocean. The figure illustrates case examples where functional groups of species have been scientifically documented to have effects on aspects of carbon cycling.
Photo detail / credit: Guanaco, Peace Parks Foundation
– Rewilding Argentina, Franco Bucci
“Our work reveals that wild animals could substantially increase an ecosystem’s carbon budget by 60–95%, and sometimes even more, relative to cases where those animals are absent.
This could potentially protect and enhance ecosystem carbon capture and storage globally by at least 6.4 billion tonnes per year. This amount rivals each of the IPCC’s top five steps for reducing net emissions expeditiously, including a rapid transition to solar and wind technology.”
Professor Oswald Schmitz of Yale School of Environment, lead author of the report and developer of the model
Photo detail / credit: European Bison
– Dan Dinu
A GROUNDBREAKING STUDY: The Reintroduction of Bison in Romania
170 European Bison, through their grazing, trampling, and seed dispersal in an area of 48 km2 of grasslands in a wider landscape of 300 km2, helped to capture approximately an additional 54,000 tonnes of CO2 per year, nearly 10 times more than without the bison.
Of grassland
Bison
Tonnes of carbon per year
Carbon capture
“These results from the Yale/GRA ACC (Animating the Carbon Cycle) model show the potential of addressing simultaneously the existential challenges of climate change and biodiversity extinctions. Allowing a comeback of nature will significantly increase the drawdown of carbon from the atmosphere while bringing back functional ecosystems and the range of ecosystem services they provide. Why look for expensive, unproven technological approaches when a natural and cost-effective solution is at hand?”
Karl Wagner, Managing Director of the Global Rewilding Alliance
ACC RESOURCES
For further information, visit our Resource Library packed with a fully searchable collection of over 60 items; articles, reports, news items, videos, scientific papers and other information about this exciting natural solution to the challenges of biodiversity loss, the climate crisis, and climate anxiety.
GET INVOLVED
If you’re a scientist working in relevent fields you can get involved with ACC by:
Diving into the research, supporting and citing the work
If you’ve got evidence that you want to submit to strengthen the case…
Receive updates on new studies & opportunities to support our efforts
SCIENTISTS & ORGANISATIONS BEHIND
This initiative is led by a partnership between the Global Rewilding Alliance and Yale School of the Environment.
This work would not have been possible without our Rewilding Champions. A great thank you to:
Biophilia Foundation, Rewilding Europe, Rewilding Chile, IFAW, André Hoffmann, Ben Goldsmith, Re:wild. We also want to thank One Earth and the WILD Foundation for helping us get started on his important initiative.
Together, this coalition advocates a very clear solution: preserving intact nature and immediately restoring and rewilding functional ecosystems at landscape and seascape scale. You can find out more about us here.