Rewilding — Restoring Nature's Carbon Engine
Rewilding is the large-scale restoration of ecosystems to the point where nature can take care of itself — allowing trophic cascades to re-establish, natural disturbance regimes to return, and native species to recover without continuous human management. It differs from conventional conservation and afforestation by targeting process rather than composition: the goal is functional ecological complexity, not a fixed species checklist. The IPCC's sixth assessment identifies nature-based solutions — including rewilding — as capable of delivering up to 10–12 Gt CO₂e/yr of mitigation by 2030, roughly 20–25% of required global emissions cuts. Rewilding is the highest-leverage, lowest-cost component of that natural-climate-solution portfolio for many biomes.
10–12 Gt CO₂e/yr
Maximum mitigation potential of all nature-based solutions by 2030 (IPCC AR6, WG3); rewilding is a key lever within this envelope alongside avoided deforestation and sustainable forestry
~3.3 Gt CO₂/yr
Estimated annual carbon sequestration from full-scale global ecosystem restoration under the UN Decade on Ecosystem Restoration (2021–2030) targets; rewilding of degraded lands is the primary driver
1.8B ha
Degraded land globally identified as suitable for ecological restoration (Etter et al. 2023, WRI Restoration Atlas); rewilding candidates represent the subset where active management can cease after initial restoration
~$10/t CO₂
Typical cost range for nature-based carbon sequestration via rewilding in temperate biomes — 3–10× cheaper than Direct Air Capture ($100–300/t CO₂) and cheaper than most industrial CCS deployments
30×30
Kunming-Montréal Global Biodiversity Framework target: protect or restore 30% of land and ocean by 2030; rewilding is the primary restoration strategy for degraded areas within this commitment
$9.5T
Annual value of ecosystem services globally (TEEB / De Groot et al.); degraded ecosystems deliver a fraction of this — full rewilding could restore the service base underpinning food, water, and climate security
★ What Rewilding Actually Means — and Why It Matters for Emissions
The term "rewilding" was coined by conservation biologists Michael Soulé and Reed Noss in 1998 to describe a continental-scale strategy based on three elements: cores (large protected wilderness areas), corridors (connectivity between cores), and carnivores (reintroducing apex predators to re-establish trophic regulation). Since then the concept has expanded into a broad framework with several distinct schools of practice:
Passive rewilding removes agricultural or forestry management and allows natural succession to proceed. This is the cheapest and most scalable approach — removing livestock from degraded uplands in Wales, Scotland, or the Appalachians, for example, and watching scrub, then woodland, return. Carbon accumulates throughout succession, from soil organic matter build-up in year one through to mature woodland carbon stocks over decades.
Translocation rewilding reintroduces lost species — herbivores, predators, or ecosystem engineers — to restore ecological processes faster than passive succession allows. Classic examples include wolf reintroduction to Yellowstone (1995) and beaver reintroduction across Europe and North America. These interventions are high-profile but affect comparatively small areas; their emissions significance lies primarily in their cascading effects on vegetation, hydrology, and soil carbon rather than in the direct biomass of the reintroduced animals.
Biome-scale rewilding involves continental or multi-national programmes targeting entire degraded biome types — the Atlantic Forest in Brazil, the Cerrado savannah, or European boreal-to-temperate corridors. At this scale, the carbon capture and ecosystem service benefits become climatically significant.
Rewilding vs. Other Restoration Approaches
| Approach | Management intensity | C sequestration rate | Time to peak C | Co-benefits |
|---|---|---|---|---|
| Rewilding (passive) | Low — remove pressure | 0.5–3.5 t CO₂/ha/yr | 30–100+ yrs | Very high: biodiversity, water, flood control |
| Afforestation (monoculture) | Medium — plant & manage | 2–6 t CO₂/ha/yr (peak mid-rotation) | 20–40 yrs | Low: carbon only, low biodiversity |
| Assisted natural regeneration | Medium-low | 1–4 t CO₂/ha/yr | 25–60 yrs | High: faster than rewilding, lower cost than planting |
| Agroforestry | High — continuous | 1–3 t CO₂/ha/yr | Ongoing | Medium: food production + C, limited wilderness |
| Peatland restoration | Medium (rewetting) | 0.5–2 t CO₂/ha/yr (stops ~1.9 Gt/yr loss) | 5–30 yrs to stabilise | High: water storage, flood control, methane risk if warm |
Source: Griscom et al. 2017 (PNAS — Natural Climate Solutions); IPCC AR6 WG3 Ch.7; Bastin et al. 2019 (Science); Cook-Patton et al. 2020 (Nature); Seddon et al. 2020 (Nature Climate Change).
Land Degradation — Scale of the Opportunity
Source: WRI Global Restoration Atlas 2023; UNCCD Global Land Outlook 2022; Etter et al. 2023; FAO 2020 State of the World's Forests.
The forest transition thesis: As countries urbanise and agricultural productivity rises, marginal farmland is abandoned and natural regeneration begins spontaneously — a process documented across Europe, the US East Coast, China, and parts of Latin America. This "passive rewilding by default" is already sequestering hundreds of millions of tonnes of CO₂ annually. Active rewilding policy accelerates and guides this transition, directing it toward high-value biodiversity corridors and securing carbon permanence through legal protection.
Rewilding vs. afforestation — the key distinction: Planting trees (afforestation) can sequester carbon rapidly in the mid-term but is vulnerable to fire, disease, and harvesting; monoculture plantations have low biodiversity value and can alter local hydrology. Rewilding allows the ecosystem to self-organise, producing structurally complex multi-species forests with higher long-term carbon permanence, lower maintenance costs, and vastly better co-benefits — but with less predictable near-term carbon trajectories. For carbon market purposes, rewilding requires a different accounting framework than plantation forestry.
Sequestration Rates by Biome — Rewilded Land
Source: Griscom et al. 2017 (PNAS); Cook-Patton et al. 2020 (Nature); Pugh et al. 2019 (Nat. Geosci.); Pan et al. 2011 (Science); Lewis et al. 2019 (Nature); IPCC AR6 WG3 Supplementary Table 7.SM.6.
Global Rewilding Carbon Potential — Breakdown by Pathway
Source: Griscom et al. 2017 (PNAS — Natural Climate Solutions portfolio); Dinerstein et al. 2020 (Science Advances — A Global Deal for Nature); Strassburg et al. 2020 (Nature); Roe et al. 2021 (Nat. Clim. Change).
Key Carbon Pathways in a Rewilded Landscape
Carbon sequestration in rewilded ecosystems occurs through multiple simultaneous pathways, which together produce total system carbon stocks far exceeding monoculture plantations:
Above-ground biomass (woody vegetation)20–250 t C/ha (succession stage dependent)
Below-ground biomass (roots)15–40% of above-ground biomass
Soil organic carbon (SOC) — top 30 cm50–150 t C/ha; increases ~0.1–0.5 t C/ha/yr under rewilding
Deadwood & coarse woody debris3–40 t C/ha; negligible in plantations; high in old-growth
Litter & forest floor (O-horizon)5–25 t C/ha
Wetland & riparian carbon (where beavers/water restored)Up to 800 t C/ha in deepened peat; largest single-site gains
Blue carbon (coastal rewilding — saltmarsh, seagrass)~4.8–87 t C/ha/yr burial rate (high variability by site)
The soil carbon premium: When grazing pressure is removed, soil carbon begins accumulating almost immediately — within the first 1–5 years. UK upland rewilding trials (Knepp Estate, Pumlumon in Wales, Trees for Life in Scotland) consistently record soil carbon gains of 0.3–0.9 t C/ha/yr within the first decade before significant tree cover establishes. Soils contain ~2,500 Gt of carbon globally — three times more than the atmosphere — making even modest increases in global soil carbon hugely significant. Rewilding's soil carbon effect is under-counted in most carbon market methodologies, which focus on above-ground biomass.
Carbon Permanence Risk Comparison
| Risk factor | Plantation forestry | Rewilded forest |
|---|---|---|
| Wildfire vulnerability | High (monoculture fuel load, no structural complexity) | Lower (mixed species, natural fuel breaks, open glades) |
| Pest & disease outbreak | Very high (monoculture, no predator regulation) | Lower (species diversity, natural predators) |
| Harvesting reversal | Very high (commercial rotations planned) | Minimal (rewilding not compatible with commercial harvest) |
| Drought stress & dieback | High for species mismatched to site | Lower (natural species selection, mixed rooting depths) |
| Policy/tenure reversal | Moderate | Moderate (requires long-term legal protection) |
Source: Anderegg et al. 2020 (Science — forest carbon sink stability); Harris et al. 2021 (Nat. Clim. Change); West et al. 2023 (Science — forest permanence); Mackey et al. 2013 (Nat. Clim. Change).
Time Profile: Carbon Accumulation under Rewilding
Source: Pugh et al. 2019 (Nat. Geosci.); Moomaw et al. 2019 (Frontiers Forests); Cook-Patton et al. 2020 (Nature — carbon accumulation rates); Poorter et al. 2016 (Nature — tropical forest regrowth).
Why Animals Are Carbon Tools
One of the most counter-intuitive findings in ecosystem ecology is that apex predators and large herbivores are significant indirect regulators of carbon storage — through their effects on vegetation structure, soil disturbance, and nutrient cycling. Removing apex predators triggers a "trophic cascade" that typically releases carbon: ungulate populations explode, overgrazing strips vegetation, soil organic matter oxidises, and stream bank erosion accelerates. Reintroducing predators reverses this process.
Yellowstone Wolf Reintroduction — The Classic Case
Following wolf reintroduction in 1995, the behavioural ecology of elk herds changed dramatically. Elk began avoiding riverbanks and valley floors (the "landscape of fear"), allowing willow, aspen, and cottonwood to regenerate in those areas. Beaver populations recovered, building dams that raised water tables, created wetland carbon sinks, and reduced peak flows. Streambank erosion declined. Carbon modelling suggests the wolf reintroduction has contributed to measurable increases in riparian vegetation carbon and soil organic carbon in affected valleys.
Wolf population at reintroduction (1995)31 individuals
Wolf population (2024)~108 in Yellowstone proper
Beaver colonies (1996 → 2022)1 → ~12 (Yellowstone NP)
Riparian woody vegetation cover (key valleys)+30–50% in released areas
Source: Ripple & Beschta 2012 (Biol. Conserv.); Smith et al. 2003 (BioScience); Beschta & Ripple 2019; Painter et al. 2018 (BioScience); Yellowstone Wolf Project Annual Reports 2024.
Beaver Rewilding — Hydrology & Carbon
Beavers are among the most cost-effective carbon tools available. A single beaver family can impound 0.5–10 ha of wetland within a few years, raising the water table across a far larger catchment. Rewetted soils accumulate carbon rapidly, reduce nitrous oxide emissions from agricultural land, and slow methane loss from dried peat. Across the UK and Europe, beaver reintroduction is accelerating following successful trials.
Area of wetland created per beaver family (avg.)~0.5–5 ha of open water
Carbon stored in beaver-created wetlands (UK trial, Devon)~0.9 t C/ha/yr above baseline
Peak flow reduction downstream30–70% in small catchments (Devon & Tayside trials)
UK beaver population target (Rewilding Britain, 2030)~2,000+ family groups
Source: Brazier et al. 2021 (Sci. Total Environ. — Devon beaver trial); Stringer & Gaywood 2016 (Scottish Natural Heritage); Berthilsson-Bernhardt et al. 2023; Law et al. 2017 (J. Appl. Ecol.); Rewilding Britain 2024 Strategy Report.
Large Herbivores — Grazing Mosaic Carbon Effects
Reintroducing native large herbivores (bison, wild horses, wisent/European bison, deer at natural densities) creates a grazing mosaic — patches of short and tall vegetation, scrub and grassland — that can increase overall landscape carbon compared with either uniform forest or heavily grazed pasture. The mechanism: heterogeneous vegetation structure captures more total light, diverse root architectures distribute carbon deeper in the soil profile, and dung beetles and soil invertebrates cycle nutrients more efficiently in ungrazed or lightly grazed patches.
| Species | Re-established range | Carbon / ecosystem role | Status |
|---|---|---|---|
| European bison (wisent) | Białowieża forest (Poland/Belarus), Transylvania, Caucasus | Grazing mosaic; bark stripping promotes deadwood; tree fall creates canopy gaps enhancing overall C density | Recovering — ~7,000 total |
| Plains bison | Tallgrass Prairie Preserve (Oklahoma), Badlands, American Prairie Reserve (Montana) | Deep-rooted prairie carbon system; 70–180 t C/ha in black soils under intact bison grassland vs. 30–60 t under cattle | ~500,000 managed animals |
| Wild horse (Przewalski) | Steppe reserves — Kazakhstan, Mongolia; Pleistocene Park (Siberia) | Compacting snow to slow permafrost thaw (Zimov hypothesis); key permafrost carbon protection role | Experimental — ~2,000 wild |
| Wild boar | Recovering across W. Europe naturally after removal of hunting pressure | Rooting creates soil disturbance that increases microbial activity; mixed effects on carbon — local disruption but seed dispersal accelerates tree regeneration | Expanded naturally |
Source: Schmitz et al. 2023 (Science — animating the carbon cycle); Bakker et al. 2016 (Nature Plants); Zimov et al. 2006 (Science — Pleistocene Park); American Prairie Reserve Carbon Reports 2023; European Bison Conservation Centre 2024.
The "animating the carbon cycle" thesis (Schmitz et al. 2023): A landmark 2023 Science paper calculated that restoring wildlife at trophic structure consistent with pre-human baselines could sequester an additional 6.4 Gt CO₂/yr globally — entirely through trophic regulation of vegetation, soil carbon, and ocean biology. Sharks and rays regulate sea-grass beds; wolves and mountain lions suppress browsing; whales fertilise phytoplankton. This animal-mediated carbon cycle has been undervalued in all climate models to date, which treat ecosystems as passive carbon stores rather than actively regulated systems.
Major Rewilding Initiatives — Scale, Progress & Carbon Expectations
| Project / Programme | Location | Area / Target | Key interventions | Carbon target |
|---|---|---|---|---|
| Rewilding Europe | 10 landscapes across 9 EU countries | 1M ha rewilded by 2030 | Bison, wild horse, deer translocation; agricultural land retirement; river restoration | ~4–6 Mt CO₂/yr when landscapes mature; primary focus is biodiversity recovery, carbon a co-benefit |
| Knepp Estate | Sussex, England | 1,400 ha (3,500 acres) — fully rewilded since 2001 | Longhorn cattle, Tamworth pigs, Exmoor ponies, deer at natural densities; all fencing removed | ~1,300 t CO₂/yr sequestered (carbon audit 2020); soil C increasing at ~0.6 t C/ha/yr; 3× pre-rewilding levels |
| American Prairie Reserve | Montana, USA (Northern Great Plains) | 500,000 ha target; ~160,000 ha secured | Bison reintroduction (1,200+ animals); cattle removal; native grassland restoration; prairie dog recovery | Intact native prairie sequesters 1.5–2.0 t CO₂/ha/yr vs. cultivated cropland; estimated 300 kt CO₂/yr at full scale |
| Wild Salmon Center — Kamchatka & Pacific NW | Russia, USA, Canada | 6M ha river basin protection | Marine nutrient cycling — salmon carcasses bring ocean-derived nitrogen and carbon into riparian forests; bear and eagle population recovery | Marine-derived nutrients increase riparian tree growth 10–20%; equivalent carbon contribution ~0.2 t C/ha/yr in salmon-rich areas |
| Atlantic Forest Restoration Pact (Brazil) | Brazil (12 Atlantic Forest states) | 15M ha restored by 2050; 300,000+ ha planted to 2024 | Passive rewilding + assisted natural regeneration; corridor connectivity; agroforestry buffers | Strassburg et al. 2020 (Nature): restoring 15% of degraded Atlantic Forest would sequester 1.45 Gt CO₂ total; offset Brazil's agri emissions for 5 years |
| Great Fen Project | Cambridgeshire, UK | 3,700 ha fen and wetland restoration | Peatland rewetting; fen grazing mosaic; bittern, crane, otter habitat restoration | ~7,000–14,000 t CO₂e/yr avoided emissions vs. degraded drained fen; soil building rate ~1 mm peat/yr once rewetted |
| Pleistocene Park | Siberia (Kolyma Basin), Russia | 144 km² protected; 160,000 km² vision | Large herbivore reintroduction (bison, musk ox, horses, reindeer) to compact snow and lower permafrost temperatures by 1–2°C | Could protect up to 30% of Siberian permafrost carbon (~100 Gt CO₂e) from near-term thaw under optimistic scaling scenario (Zimov et al.) |
| African Wildlife Foundation — Rewilding Savannah | Kenya, Tanzania, Zambia, Mozambique | Multiple landscapes; 2M ha target | Wildlife corridor restoration; anti-poaching to recover elephant populations; community land tenure reform | Elephants as "ecosystem engineers": create forest gaps promoting C-rich secondary growth; estimated ~8,000 t CO₂/yr per 1,000 elephants in forested landscapes (Berzaghi et al. 2019) |
Source: Rewilding Europe Annual Report 2024; Knepp Estate Carbon Audit 2020; American Prairie Reserve Environmental Reports 2023; Strassburg et al. 2020 (Nature — Atlantic Forest); Zimov et al. 2006 (Science); Berzaghi et al. 2019 (Nat. Geosci. — African forest elephants); Wild Salmon Center 2024.
Scaling challenge — the "missing middle": Most rewilding projects are either very small (individual farms, 100–2,000 ha) or aspirationally very large (millions of hectares, multi-decade timelines). The "missing middle" — landscape-scale programmes of 10,000–200,000 ha with concrete 10-year carbon and biodiversity targets — remains underfunded. This is where voluntary carbon markets, blended finance structures, and payment-for-ecosystem-services frameworks need to develop to unlock the full mitigation potential identified by the IPCC.
Cost of Carbon Sequestration — Rewilding vs. Alternatives
Source: Griscom et al. 2017 (PNAS); Fuss et al. 2018 (Nature Clim. Change); IEA CCUS 2023; Hanna et al. 2021 (Energy & Environ. Science — DAC cost); IETA 2024 Voluntary Carbon Markets; ETH Zurich reforestation cost survey 2023.
Rewilding Ecosystem Service Value — Beyond Carbon
Source: De Groot et al. 2012 (Ecosystem Services); TEEB Foundations 2010; Costanza et al. 2014 (Global Environ. Change); Rewilding Britain Economic Valuation 2021; IUCN Green List Standards.
Revenue & Funding Models for Rewilding
| Model | Mechanism | Current scale | Carbon revenue per ha/yr | Maturity |
|---|---|---|---|---|
| Voluntary carbon credits (VCM) | Verified carbon units (VCUs) under Verra VCS or Gold Standard sold to corporates; requires additionality and permanence proof | ~$2B/yr VCM globally for nature-based; <20% is rewilding-specific | $5–40/t CO₂ × sequestration rate | Developing — methodologies still maturing |
| Biodiversity net gain (BNG) | UK mandate (Environment Act 2021): developers must deliver 10% biodiversity net gain; rewilding sites sell "biodiversity units" | ~£50M/yr UK market (2024–25); scaling to £200M+ by 2027 | £500–2,000/ha/yr for high-value habitat | Live in England since Jan 2024 |
| Payment for ecosystem services (PES) | Government or water utility payments for flood attenuation, water quality, catchment management | Widespread in EU (agri-environment schemes); growing in USA (USDA RCPP) | $50–300/ha/yr depending on service valued | Established framework |
| Nature tourism / eco-tourism | Direct visitor revenue from wildlife experiences on rewilded land | Knepp earns ~£400k/yr from safaris and glamping; African rewilding projects generate $1,000–4,000/ha/yr | Indirect — displaces C revenue need | Proven at scale in Africa |
| Blended conservation finance | Philanthropic capital (grants) + debt (green bonds) + equity (returns from nature income); de-risks private investment | TNFD framework (2023) catalysing institutional interest; TNC's NatureVest ~$1.5B deployed | N/A — reduces financing cost of whole project | Growing rapidly post-TNFD |
Source: Ecosystem Marketplace 2024 (VCM); UK BNG Market Guidance (Natural England 2024); USDA RCPP programme data; Knepp Estate financials (Rewilding Britain 2023); TNC NatureVest Portfolio Report 2024; TNFD Guidance Framework v1.0 2023.
The opportunity cost problem: The primary economic barrier to rewilding is not cost per se, but the foregone income from agricultural or forestry use of the land. In Scotland, rewilding upland hill farms means giving up sheep subsidies (~£60–120/ha/yr under the old CAP regime). Carbon credits and PES payments must at minimum replace this opportunity cost to make rewilding financially viable without philanthropy. With Scotland's new Agriculture (Scotland) Act 2024 shifting subsidies toward environmental outcomes, the economics are rapidly improving — rewilding may soon be the highest-income land use in many marginal upland areas.
The Policy Landscape — From 30×30 to National Strategies
Rewilding has moved from a fringe conservation idea in the 1990s to a mainstream policy instrument in the 2020s, driven by three converging policy frameworks: the Kunming-Montréal Biodiversity Framework (30×30), the EU Nature Restoration Law, and the IPCC's identification of nature-based solutions as a critical near-term mitigation tool.
Key Policy Frameworks Enabling Rewilding
| Framework | Scope | Rewilding relevance | Status (May 2026) |
|---|---|---|---|
| Kunming-Montréal GBF — 30×30 | Global; 196 parties | Requires 30% of land and ocean under protection or restoration by 2030; rewilding is the primary restoration mechanism for degraded land | Adopted Dec 2022; 100+ countries with NBSAPs submitted |
| EU Nature Restoration Law | EU-27 | Legally binding: restore 20% of EU land and sea by 2030, 100% of degraded ecosystems by 2050; explicit rewilding language in preamble | In force since Aug 2024 |
| IPCC AR6 — Natural Climate Solutions | Global scientific guidance | Identifies 10–12 Gt CO₂e/yr NbS potential; forest restoration and rewilding = 3.9 Gt of that; cost below $100/t for most pathways | Ongoing — AR7 begins 2027 |
| UK Environment Act 2021 | England/UK | Mandatory biodiversity net gain; targets to halt species decline by 2030; land management payments (ELMS) reward rewilding outcomes | BNG mandatory since Jan 2024 |
| US Inflation Reduction Act — Forestry & Ag provisions | USA | $20B for conservation and agriculture; USDA RCPP funds rewilding-compatible conservation easements and habitat restoration | Enacted Aug 2022; funding ongoing |
| UNFCCC — Article 5 (Paris) | Global | Recognises role of sinks and reservoirs; countries can include rewilding in NDC land-use targets under LULUCF accounting | NDC cycle 3.0 submissions due 2025 |
Source: CBD Secretariat 2022 (GBF text); EU Nature Restoration Law (EU) 2024/1991; IPCC AR6 WG3 2022; UK Environment Act 2021; IRA text (Public Law 117-169); UNFCCC Paris Agreement Article 5.
Country-Level Rewilding Commitments (2026)
Source: IUCN 2024 Rewilding Country Commitments Survey; RSPB / Rewilding Britain policy tracker 2025; Rewilding Europe Policy Monitor Q1 2026.
The additionality and permanence debate: Carbon markets require that rewilding carbon credits are additional (would not have happened anyway) and permanent (carbon will not be re-released within 100 years). Both criteria are problematic for rewilding on currently marginal farmland: passive regeneration may happen even without funding (low additionality), and political or ownership changes can reverse protection. The voluntary carbon market is actively developing new methodologies (e.g., Verra's Jurisdictional and Nested REDD+, the new ART-TREES national framework) to address permanence through jurisdictional-level accounting rather than project-level buffer pools. Until these are mainstream, rewilding's primary carbon finance route is biodiversity credits and PES rather than VCM.
The "rewilding vs. food security" tension: Large-scale rewilding of agricultural land raises food sovereignty concerns, particularly in countries dependent on domestic production. Analysis by Rewilding Britain (2022) suggests that rewilding 5% of UK land — primarily semi-improved upland grassland with very low agricultural productivity — would reduce domestic food production by less than 1% while delivering biodiversity, carbon, and flood attenuation benefits worth multiples of the lost agricultural value. The framing matters: rewilding proposals targeting low-productivity marginal land face far less political resistance than those targeting productive agricultural land.