A systematic review of nature-positive climate risk transfer and financing instruments

communications earth & environment Article A Nature Portfolio journal https://doi.org/10.1038/s43247-026-03388-0 A systematic review of nature-positive climate risk transfer and financing instruments Check for updates 1234567890():,; 1234567890():,; Alina Bill-Weilandt Perrine Hamel 1,2 1,2,3 , David Lallemant 1,2 , Vivien Chan 1 , Meherwan Rohinton Patel 1 & Nature-based solutions can strengthen climate resilience, but they remain underfinanced. Innovative financial instruments that transfer or reduce climate risk while enhancing ecosystem services help close the adaptation and nature finance gaps. Here we synthesize evidence on nature-positive climate risk transfer and financing instruments, with attention to how the effectiveness and economic viability of supported nature-based interventions are reported. We screened ~3,200 academic publications and 78 institutional databases, identifying 33 distinct nature-positive financial instruments. We introduced a typology that organizes them by financial instrument category. This typology, alongside a global database of 313 projects found in the literature and an inventory of 76 implemented projects, supports replication, adaptation, and scaling of nature-based solutions in diverse contexts. The systematic review highlights evidence gaps, including limited equity considerations and uncertainties in risk modeling. Together, the typology, inventory, and synthesis provide a foundation for advancing nature-positive finance through future research, investment, and policy design. Five of the ten most severe risks in the next decade are environmental, according to the Global Risk Report 20261, with extreme weather events, biodiversity loss and ecosystem collapse, and critical changes to Earth systems ranking as the top three. Nature-based Solutions (NBS) for climate resilience offer great opportunities to address the crises of climate change, biodiversity loss, and land degradation in an integrated way. NBS are “actions to protect, conserve, restore, sustainably use and manage natural or modified […] ecosystems which address social, economic and environmental challenges effectively and adaptively, while simultaneously providing human well-being, ecosystem services, resilience and biodiversity benefits”2. The term NBS is an umbrella term including other approaches like ecosystem-based mitigation, ecosystem-based adaptation, and ecosystem-based disaster risk reduction3. NBS for climate resilience aim to reduce climate and disaster risk by regulating at least one climate-related hazard. Examples include the protection of mangroves, which attenuate wave energy and protect coastal communities4, and the preservation of forests, which reduce flood volumes and protect adjacent agricultural fields5. Compared to gray infrastructure, NBS can address a broader range of societal challenges beyond disaster risk, including climate change, food security, water security, human health, and social and economic development3. Given their potential to regulate climate risks and address multiple societal challenges6,7, NBS have gained substantial attention in global policy discussions. International agreements like the Sendai Framework for Disaster Risk Reduction 2015–20308, the Agenda 2030 for Sustainable Development8, the Paris Agreement9, and the Kunming-Montreal Global Biodiversity Framework10 acknowledge the need to advance NBS and climate risk finance. Over 80% of the updated Paris Agreement climate pledges include NBS11. However, despite the political pledges, the nature and climate finance gaps remain large. Global investments in NBS amounted to about USD 200 billion per year in 2022, with public funds accounting for 82% and private finance for 18%. However, investments would need to nearly triple to USD 542 billion by 2030 to achieve climate, biodiversity, and land degradation neutrality targets12. Low- and middle-income countries are especially challenged to protect, manage, and restore natural assets with limited budgets. In 2022, finance flows to NBS accounted for only one percent of the total Overseas Development Assistance12. In February 2025, governments worldwide agreed to mobilize USD 200 billion annually by 2030 - including USD 30 billion in international flows - to achieve the goals of the Global Biodiversity Framework13. Research on constraints to NBS implementation found that financing of NBS is a central barrier and advocated for systematic reviews on this 1 Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore. 2Asian School of the Environment, Nanyang Technological University, e-mail: Singapore, Singapore. 3Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, Potsdam, Germany. Communications Earth & Environment | (2026)7:318 1 https://doi.org/10.1038/s43247-026-03388-0 topic14. A systematic review of systematic reviews on NBS for climate adaptation identified NBS financing as a key research gap, also finding little evidence on “social issues” and “the role(s) of the private sector”15. Recognizing this research gap, the European Commission created a task force titled ‘business models and financing for NBS’ as one of four task forces on NBS under the Horizon 2020 program16. A scoping review defined alternative financing (AF) models for NBS as “arrangements that draw on financial resources other than public budgets collected through general taxation”17. It proposed a typology classifying AF models, among others, based on who finances and who funds them. The review emphasized that drivers and barriers associated with AF for NBS depend on the broader political, economic, social, technological, legal, and environmental context of NBS, resulting in a need to address these aspects in parallel to successfully finance NBS. It called for a systematic assessment of existing AF models and their context to understand their state of development, local applicability, and scalability17. The review identified “NBS monitoring, quantification, valuation, and monetization” as a gap in NBS financing research17. Reviews of finance for urban NBS18 and NBS in Europe19 have identified valuation and accounting of NBS benefits and effectiveness, along with coordination across public and private financiers and reliance on public resources, as key financing barriers and challenges to NBS implementation. They advocated for private sector involvement in NBS financing “through (innovative) economic and financial instruments”19 and recommended “a systematic review on the sources of finance for (different types of) NBS” across ecological domains, considering valuation and accounting methods for NBS benefits18. Recent reviews continue to recognize the potential of innovative and AF mechanisms for NBS involving insurers and the private sector and identify it as a research gap20. A systematic review of 155 articles found that the public sector is the primary financing source of NBS for reducing disaster risk21. The (...truncated)