Biodiversity Implications of Land-Intensive Carbon Dioxide Removal
- Jun 17
- 6 min read
A 2026 multimodel study finds 1.5°C-consistent climate pathways allocate up to 13% of global biodiversity refugia to land-intensive carbon removal, with disproportionate impacts on low-income countries.
Climate mitigation pathways and biodiversity conservation are often treated as naturally aligned goals — both, after all, depend on healthy, functioning ecosystems. But the pathways that climate models generate to limit warming to 1.5°C or 2°C rely overwhelmingly on land-intensive carbon dioxide removal: afforestation, reforestation, and bioenergy with carbon capture and storage (BECCS), deployed at a scale measured in billions of tonnes of CO₂ and, correspondingly, hundreds of millions of hectares of land. Where exactly that land comes from, and whether it overlaps with the planet's most ecologically irreplaceable places, has remained a largely unanswered question in the modeling pathways that inform global climate policy.
Prütz et al. (2026) tackle this question directly, performing the first multimodel assessment of CDR-related land allocation against detailed biodiversity data covering around 135,000 terrestrial species and more than 170 global biodiversity hotspots — and find that the most ambitious climate scenarios carry the highest biodiversity costs.
Key Findings
A Multimodel Framework Spanning Five Integrated Assessment Models
The study draws on land-use and carbon removal data from five integrated assessment models (IAMs) — AIM, GCAM, GLOBIOM, IMAGE, and REMIND-MAgPIE — applied to scenarios representing three levels of mitigation ambition: a current-policies trajectory roughly consistent with RCP4.5, a 2°C-consistent pathway based on RCP2.6, and a highly ambitious 1.5°C pathway based on RCP1.9. Biodiversity is assessed using two complementary metrics: climate refugia, defined as areas where at least 75% of the roughly 135,000 considered species (fungi, plants, invertebrates, and vertebrates) would remain under a given level of global warming; and biodiversity hotspots, areas of exceptional species richness and endemism drawn from established conservation datasets.
By overlaying spatially explicit projections of forestation and bioenergy cropland expansion against these biodiversity layers, the study traces how CDR land allocation evolves from 2020 through 2100, and identifies where, geographically, climate mitigation infrastructure and biodiversity conservation priorities come into direct spatial conflict.
The More Ambitious the Climate Target, the Greater the Biodiversity Overlap
A central and somewhat counterintuitive finding is that biodiversity overlap scales with mitigation stringency rather than against it. Under current policies, the share of land-intensive CDR situated within remaining climate refugia stays consistently below 6%. That figure rises to up to 9% under 2°C-consistent scenarios, and climbs further to as much as 13% under 1.5°C-consistent scenarios. The explanation is not that more ambitious pathways cause more direct biodiversity loss from warming — in fact, they substantially reduce warming-related refugia loss compared to the current-policies trajectory — but that they depend so heavily on land-intensive CDR that the resulting land footprint increasingly intrudes on the climate refugia that ambitious mitigation is, in principle, trying to protect.
Within this land allocation, forestation claims considerably more refugia area than BECCS: by the end of the century in 1.5°C scenarios, up to around 11% of remaining climate refugia is allocated to forestation, compared to up to around 4% for the conversion of land to bioenergy cropland. The scale of forestation-related overlap also varies sharply by model — the AIM model allocates considerably more refugia land to forestation than GLOBIOM or IMAGE — while BECCS-related land allocation is comparatively consistent across the three models capable of producing this analysis.
The Net Effect Remains Genuinely Uncertain
To move beyond raw land allocation figures, the study calculates an illustrative "net" biodiversity effect: the share of climate refugia that CDR deployment would help preserve through avoided warming, minus the share of refugia allocated to CDR land use (conservatively assuming that all such land allocation is fully harmful to biodiversity). The resulting net effect tends toward a modest benefit — CDR-related avoided warming could reduce long-term climate refugia loss by up to roughly 25% in the scenarios assessed — but this finding is highly sensitive to one critical and still-unresolved assumption: whether climate refugia can recover after a period of temperature overshoot. If refugia do not recover once peak warming has passed, the protective value of CDR's avoided warming shrinks substantially, and the net effect can tip toward harm rather than benefit.
A Disproportionate Burden Falls on Lower-Income Countries
The study identifies a clear and troubling geographic pattern: when refugia allocation is examined through the lens of the UNFCCC's Annex I / non-Annex I classification, non-Annex I countries — predominantly low- and middle-income nations — see up to 15% of their remaining climate refugia allocated to forestation, compared to around 7% in Annex I (industrialized) countries. This represents what the authors describe as a dual inequity: countries that bear the least historical responsibility for causing climate change face the compounded burden of both preserving their biodiversity and hosting the land-intensive carbon removal infrastructure that wealthier nations' mitigation pathways depend upon. No equivalent disparity was found for BECCS-related land allocation.
At a more granular level, even moderate carbon removal volumes generate substantial relative pressure in some countries. Using a common removal benchmark of 6 gigatonnes of CO₂ across three models, the study finds that countries with very little remaining climate refugia to begin with often show the highest relative allocation shares — even when the absolute area involved is small. By contrast, countries like the United States, which retain large areas of intact climate refugia at 1.8°C of warming, show comparatively low relative allocation despite hosting large absolute volumes of CDR deployment.
Mapping Where Conflict and Synergy Are Most Likely
Cross-referencing land allocation against independently derived maps of ecologically suitable reforestation potential and biodiversity-compatible bioenergy cropland potential, the study identifies specific global regions where at least two of the five models converge on deploying CDR within climate refugia, allowing a first-order distinction between likely harmful and potentially beneficial overlaps. The clearest areas of model consensus lie in Eastern China for forestation, and in parts of the United States, West Africa, and Indo-Pacific island states for BECCS. The majority of these consensus regions fall into areas identified as unsuitable for land-intensive CDR — refugia without genuine reforestation potential, in the case of forestation, or bioenergy cropland that interferes with broader biosphere integrity, in the case of BECCS — though a smaller number of consensus areas were identified as potentially beneficial, where carefully implemented forestation or bioenergy cropland could align with both carbon and biodiversity goals.
What Strict Conservation Targets Would Mean for Carbon Removal
Beyond mapping where conflicts currently arise in modeled pathways, the study runs a forward-looking thought experiment: what happens to CDR land availability if biodiversity protection commitments, such as the Kunming-Montreal Global Biodiversity Framework's target of halting the loss of areas of high biodiversity importance, were strictly enforced.
More than half of currently modeled CDR land would vanish under strict hotspot protection: If current biodiversity hotspots were entirely excluded from land-use change, more than 50% (median estimate across models) of the land allocated for forestation and BECCS in the 2°C focus scenario would become unavailable by as early as 2030, and this constraint remains largely stable through 2050 and 2100.
The constraint is not a hard ceiling on mitigation, but it does raise the cost of land: Models retain the flexibility to relocate CDR land allocation to less cost-effective locations, shift toward less land-intensive mitigation options, or adopt more biodiversity-sensitive deployment strategies — but doing so increases overall competition for land, compounding existing pressures from fire risk, food security, and other planetary boundary constraints not addressed by this biodiversity-specific study.
Restoration-oriented approaches can deliver genuine synergies: The relationship between CDR and biodiversity is not inherently adversarial: forest restoration using diverse, locally adapted species on land that was historically forested can simultaneously expand and reconnect habitat while sequestering more carbon than fast-growing monoculture plantations, and carbon stored in natural ecosystems tends to be more resilient to climate change than carbon in managed plantations. The risk lies specifically in misapplied afforestation — planting trees in naturally treeless ecosystems such as savannas and grasslands, which has historically harmed biodiversity while delivering questionable carbon benefits.
A widening biodiversity finance gap compounds the equity problem: Given the global biodiversity finance gap estimated at US$700 billion per year, and the disproportionate refugia burden already falling on non-Annex I countries, the study argues that industrialized nations bear an obligation to substantially increase biodiversity-related financial flows to the lower-income countries hosting much of the modeled CDR land base.
The Land Beneath the Climate Target
Carbon dioxide removal has often been discussed in the abstract — as a quantity of gigatonnes, a line on an emissions chart, a wedge in a mitigation pathway. Prütz et al.'s study insists on a more concrete reckoning: that gigatonne figure corresponds to real land, often in some of the planet's most biologically irreplaceable places, and disproportionately in countries that did the least to cause the warming those removals are meant to counteract.
The most ambitious climate targets, paradoxically, generate the greatest pressure on this land precisely because they rely most heavily on the CDR options that consume it. None of this makes land-intensive carbon removal inherently incompatible with biodiversity conservation — done through ecological restoration rather than indiscriminate afforestation, it can serve both goals at once. But it does mean that the climate community can no longer treat the location of carbon removal as an afterthought to its volume. Where the trees go matters nearly as much as how many there are.
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