Impact Assessment Frameworks for Nature-Based Climate Solutions: A Review of Contemporary Approaches

This study provides a comparative analysis of ecological impact assessment (EcIA) guidance for the design and approval stages of carbon sequestration and emission reduction projects, which are rapidly proliferating in response to the global need for climate change mitigation. Previous reports of negative effects on biodiversity from such projects suggest a need for more robust project design and assessment processes to improve synergies with conservation. Using a content and thematic analysis methodology, we compared four published frameworks that guide the assessment of carbon projects in natural environments. The results showed considerable variation in environmental assessment components including the level of attention to ecosystem services and the identification of areas of high conservation value that may require specific protections. There was a general lack of guidance on the inclusion of indirect and supply chain effects despite their relevance to ecological impacts. Critically, guidance in common use in the climate mitigation sector shows differing applications of the baseline and counterfactual scenarios that are used to quantify impacts. We discuss the need to focus assessment and reporting on comparisons with recent baselines to identify the contributions of individual projects and enable adaptive management and show how aligning with the concepts of Nature-based Solutions and nature-positive could be used to reimagine the role of EcIA to achieve these objectives. If these current weaknesses can be improved, EcIA has the potential to become an important implementation pathway for the conservation–climate change nexus due to its pivotal role in project design and approval processes. Conversely, a failure to reliably address these aspects will undermine the utility of EcIA as a decision support tool for sustainable development. We encourage the further exploration of EcIA practices in this direction and highlight the pressing need for reliable comparisons to support more strategic and sustainable solutions for both the conservation and climate change agendas.