Biodiversity and climate: why the two agendas must converge in your impact assessments

The Convention on Biological Diversity (CBD, 1992) and the United Nations Framework Convention on Climate Change (UNFCCC, 1992) were born in the same year, at the Rio Earth Summit. They evolved in parallel for three decades, with separate secretariats, distinct expert communities, desynchronised political calendars. This separation contributed to establishing, in impact assessment methodologies, a compartmentalisation between biodiversity analysis and climate analysis.

Convergence is now taking place. Joint reports by the IPCC and IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services), the rise of nature-based solutions, the development of the Taskforce on Nature-related Financial Disclosures (TNFD) in parallel with TCFD, are converging the two agendas in assessment frameworks. DFI lenders are following this movement, with increasingly frequent cross-cutting requirements in project reviews.

For a project owner or an E&S consultant, this convergence changes how an ESIA must be structured. The biodiversity and climate sections can no longer function in silos. They must dialogue across several dimensions: common impacts, common solutions, cross-cutting risks.

This article presents the three major dimensions of convergence, the methodological implications for impact assessment, emerging tools, and the pitfalls to avoid in the transition.

Dimension 1: climate as a pressure factor on biodiversity

The first obvious convergence is that climate change has become one of the main causes of biodiversity loss. Environments are drying out, species distributions are shifting, ecological interactions are destabilising, extreme events are destroying habitats that ecosystems took decades to rebuild.

For an impact assessment, this means that biodiversity analysis must integrate climate projections to properly assess the probable evolution of ecosystems over the project lifetime. A habitat that appears robust in 2026 may be significantly degraded in 2050 under the combined effects of the project and climate. Ignoring this dual pressure leads to underestimating cumulative impacts.

The methodology consists of characterising the climate sensitivity of ecosystems present in the project area, projecting probable climate conditions, and assessing project impacts in this future context rather than in the present context alone. This demanding approach produces fairer assessments and better calibrated mitigation measures.

Dimension 2: biodiversity as a climate regulator

The symmetrical convergence concerns the role of ecosystems in climate regulation. Forests absorb carbon, mangroves mitigate coastal erosion and sea-level rise, wetlands massively store carbon and regulate flooding, grasslands durably sequester carbon in soils.

Destruction of these ecosystems not only releases direct emissions (combustion or decomposition of destroyed biomasses) but reduces future sequestration capacity. An infrastructure project that fragments a tropical forest or fills in a mangrove produces a major climate impact, often not integrated into its carbon footprint calculated according to the classic GHG Protocol alone.

Emerging methodologies, particularly those advanced by the Natural Capital Protocol and the work of the Science Based Targets Network, integrate this dimension. They assess affected ecosystem services, including climate regulation services, and monetise or quantify them according to available methods.

For an impact assessment, the practical consequence is that the climate chapter cannot be limited to the footprint of project activities. It must integrate emissions linked to ecosystem losses as well as the reduction in sequestration capacities.

Dimension 3: common solutions (nature-based solutions)

The third dimension is the most operationally fruitful. Several measures simultaneously address biodiversity and climate issues: nature-based solutions.

Restoration of degraded ecosystems: reforestation of tropical forests, mangrove restoration, wetland rehabilitation. These actions produce measurable co-benefits: carbon sequestration, biodiversity hosting, protection against climate hazards, services to local communities.

Preventive conservation: active protection of ecosystems that would otherwise have been degraded. This approach avoids future emissions whilst preserving biodiversity. It is at the heart of REDD+ mechanisms deployed for over fifteen years.

Integration of green infrastructure. Vegetated urban developments, ecological corridors along transport routes, landscape buffer zones between industrial installations and residential areas, simultaneously produce climate benefits (reduction of heat islands, absorption of rainwater, sequestration) and biodiversity benefits (maintenance of ecological continuities, hosting of auxiliary species).

For an infrastructure project, these solutions often offer mitigation levers that do not exist with classical technical approaches. A mangrove restoration programme associated with a port project can compensate a substantial portion of residual impacts, at a cost often lower than purely technical alternatives.

Integration in an impact assessment

Recent developments in DFI frameworks encourage the integration of biodiversity and climate analyses, without however structuring it as formally as some would like.

IFC Performance Standard 6, in its latest revision, integrates explicit references to the climate resilience of ecosystems and their role in climate regulation. The World Bank ESS6 also addresses ecosystem services, including climate services. TNFD, whose final framework was published in 2023, proposes a common methodological approach for jointly analysing climate and nature-related risks.

For an ESIA, operational integration involves three concrete actions.

Firstly, conduct ecosystem sensitivity analyses integrating climate scenarios, not just historical data. A biological inventory conducted without climate reading produces an instantaneous snapshot of a situation in motion.

Secondly, calculate GHG emissions linked to ecosystem losses in the project's carbon footprint. This biogenic accounting relies on public methodologies documented by the IPCC and specialised agencies.

Thirdly, systematically evaluate nature-based solutions as alternatives to technical mitigation measures. This assessment is an integral part of the alternatives analysis required by lenders.

Emerging tools

Several tools structure the integrated biodiversity-climate approach.

The Natural Capital Protocol, a methodological framework published by the Natural Capital Coalition, proposes a standardised approach for assessing a company's impacts on natural capital, including biodiversity and climate dimensions.

TNFD (Taskforce on Nature-related Financial Disclosures), published in its final version in September 2023, proposes a reporting framework complementary to TCFD, focused on nature-related risks. Its deployment amongst international financial institutions should accelerate in coming years.

Science Based Targets for Nature (SBTN), currently being deployed, aim to provide companies with quantified targets on nature, similar to what Science Based Targets climate have done for emissions.

For an infrastructure project, these tools are not yet contractually required by the majority of lenders, but they structure the evolution of expectations. Projects that integrate them today position themselves favourably for future financing.

Pitfalls to avoid in the transition

Four pitfalls recur in initial attempts at biodiversity-climate integration.

Climate compensation through biodiversity destruction. A project that plants monospecific plantations to offset its emissions may display a positive climate contribution at massive biodiversity expense. This type of solution, frequent ten years ago, is now explicitly rejected by serious frameworks.

Biodiversity compensation through climate emissions. Symmetrically, ecosystem restoration can mobilise activities (material transport, equipment) that generate significant emissions. The analysis must present a net balance, not a balance on the single highlighted aspect.

Scale confusion. Climate analyses classically operate at global or regional scales, biodiversity analyses at more local scales. This scale difference produces reading biases when both are combined without precaution.

Over-promising nature-based solutions. Some solutions presented as miracles (massive reforestation, wetland restoration) do not always deliver their promises in practice. Additionality, permanence, measurability are criteria to apply as strictly as for classical biodiversity offsets.

The convergence of biodiversity and climate agendas is not a methodological fashion, it is a long-term correction that finally rejoins the ecological reality of studied environments. For an impact assessment, it means more rigour, more complexity, but also more relevance to the real issues of an infrastructure project.

Stakeholders who integrate this convergence into their methodologies give themselves a sustainable methodological advantage. Tools exist, frameworks are evolving, lenders actively encourage the approach. The entry cost is modest, the benefits in credibility and decision robustness are real.