Biodiversity Faces Compounding Threats as Extreme Heat, Land-Use Change, and Carbon Removal Tradeoffs Converge
An Oxford-led study warns nearly 8,000 vertebrate species face unsuitable conditions by 2100 from combined heat and land-use stress, while a separate Nature Climate Change paper finds that protecting biodiversity hotspots would halve the land available for forestation-based carbon removal.
Twin Pressures on a Shrinking Habitat
Two lines of research published in recent months are sharpening the scientific picture of what biodiversity faces in the coming decades. One quantifies the direct threat that extreme heat and land-use change pose to thousands of vertebrate species. The other reveals a structural tension at the heart of climate policy itself: the land that governments and modelers have earmarked for carbon dioxide removal through forestation overlaps significantly with the world’s most biologically important areas. Together, the findings suggest that biodiversity is caught between the immediate pressures of a warming planet and the unintended consequences of strategies designed to cool it.
Nearly 8,000 Species at Risk from Heat and Land-Use Change
A study published in Global Change Biology in December 2025, led by Dr. Reut Vardi of the University of Oxford’s School of Geography and the Environment, assessed nearly 30,000 species of amphibians, birds, mammals, and reptiles to determine how the combined effects of future extreme heat events and projected land-use changes would alter habitat suitability.
The results are severe. Under the worst-case emissions scenario, up to 7,895 vertebrate species could face unsuitable conditions across their entire range by 2100, with affected species experiencing unsuitable conditions across an average of 52 percent of their current habitat. Even the most optimistic scenario projects that 10 percent of species’ ranges would become unsuitable.
The geographic distribution of risk is uneven. The Sahel, the Middle East, and Brazil emerge as regions where heat stress and habitat conversion interact most acutely. Under two of the modeled scenarios, more than 77 percent of data-deficient species, over 50 percent of near-threatened species, and more than 60 percent of species already classified as threatened face unsuitable conditions across at least half their range.
“Our research highlights the importance of considering the potential effects of multiple threats together to get a better estimation of their potential impact,” Vardi said. The study’s significance lies in treating heat extremes and land-use change as interacting forces rather than independent variables, a methodological shift that yields substantially higher risk estimates than single-threat assessments.
Carbon Removal and Biodiversity on a Collision Course
A paper published in Nature Climate Change in March 2026 by Ruben Prütz and colleagues at the Potsdam Institute for Climate Impact Research introduces a different dimension to the crisis. The study examined how land-intensive carbon dioxide removal methods, primarily forestation and bioenergy with carbon capture and storage, interact with areas of high biodiversity importance in climate mitigation scenarios.
The core finding is that scenarios consistent with limiting warming to 1.5 degrees Celsius allocate up to 13 percent of globally significant biodiversity-rich lands for carbon dioxide removal projects. If those biodiversity hotspots were fully protected from land-use change, more than half the land designated for forestation and bioenergy-based carbon removal in the assessed scenarios would become unavailable.
The analysis covered approximately 135,000 species across fungi, invertebrates, plants, and vertebrates, substantially expanding the taxonomic scope beyond previous assessments that typically examined around 25,000 species. The geographic distribution of the conflict is itself a source of concern: the models allocate considerably more land for forest-based carbon removal in the Global South than in the Global North, concentrating the biodiversity tradeoffs in regions that are already biologically rich and ecologically vulnerable.
A companion perspective in Nature Climate Change emphasized that careful spatial planning of carbon removal projects is critical and that synergies between carbon sequestration and biodiversity conservation are possible but require deliberate design. The Prütz study itself found that carbon dioxide removal could help maintain 25 percent more habitat for biodiversity compared to projections without any removal, but only if emission reductions proceed in parallel. Relying primarily on land-based carbon removal without aggressive decarbonization provides insufficient climate protection and amplifies the pressure on ecosystems.
Freshwater Species Under Parallel Strain
The pressures documented in terrestrial systems have parallels in freshwater ecosystems. A comprehensive assessment published in Nature covering 23,496 species of decapod crustaceans, fishes, and odonates found that one-quarter of global freshwater fauna is threatened with extinction. The study represents the most complete multi-taxon evaluation of freshwater biodiversity to date and identifies habitat degradation, pollution, and overexploitation as the primary drivers.
The freshwater findings intersect with the terrestrial research in an important way. Many forestation and bioenergy projects affect water systems through changes in hydrology, water extraction, and runoff patterns. The Prütz study did not model freshwater impacts directly, but the overlap between terrestrial carbon removal footprints and watershed areas suggests an additional layer of ecological risk that current climate models may underestimate.
Migration Corridors Under Climate Stress
The consequences of habitat fragmentation extend beyond static measures of range suitability. A study published in PLOS Climate in February 2026 by Francisco Botello and Carolina Ureta of the National Autonomous University of Mexico projected that suitable habitat for monarch butterflies in Mexico could decline by 8 to 40 percent by 2070. The research found that areas of highest climatic and biological suitability are shifting southward, away from the Mexico-United States border, fragmenting the migration corridors that the species depends on for its transcontinental journey.
The monarch case illustrates a broader pattern. Species that depend on large-scale seasonal movements are disproportionately vulnerable to the kind of habitat mosaics created when climate change, land-use conversion, and carbon removal projects fragment previously continuous landscapes. The Oxford study’s finding that the Sahel and Brazil face particularly acute compounding pressures maps onto regions that host some of the world’s most significant migratory flyways and corridors.
The Policy Bind
The cumulative picture is of a policy landscape in which the tools designed to address climate change can, if poorly implemented, accelerate the biodiversity crisis they are partly intended to mitigate. The Kunming-Montreal Global Biodiversity Framework, adopted in 2022 with a 2030 deadline for measurable progress, calls for protecting 30 percent of land and sea areas. The Paris Agreement’s carbon removal pathways, meanwhile, assume the availability of vast tracts of land for forestation and bioenergy.
The Prütz study makes the tension explicit: meeting both sets of targets simultaneously requires spatial precision that current planning frameworks do not yet deliver. Protecting all biodiversity hotspots from carbon removal projects cuts the available land by more than half. Ignoring biodiversity in the rush to sequester carbon risks undermining the ecological systems that provide climate resilience, from forests that regulate regional weather to wetlands that buffer against flooding.
The research does not suggest that carbon removal and biodiversity conservation are irreconcilable. It does suggest that treating them as separate policy silos, managed by different international agreements with different monitoring systems and different political constituencies, produces outcomes that are worse for both. The 7,895 species identified in the Oxford study as facing unsuitable conditions by century’s end will not distinguish between habitat lost to a palm oil plantation and habitat lost to a carbon offset forest. The question is whether policymakers will.