Unpacking Methods for Integrated Assessments of Nature-Based Solutions

The guide outlines a five-step methodology to integrate nature-based solutions into project lifecycles, moving from qualitative systems thinking to quantitative economic valuation. It emphasizes the use of systems mapping, climate data analysis, and scenario modeling to compare NbS against traditional 'grey' infrastructure and 'business as usual' scenarios. The framework concludes with strategies for identifying financing structures and communicating findings to diverse stakeholders.

• Nature-based solutions (NbS) are defined as interventions that are "inspired and supported by nature", designed to be "cost-effective" while providing simultaneous "environmental, social and economic benefits" and enhancing resilience across cities, landscapes, and seascapes.
• The guide proposes a five-step process for integrated assessments: (1) identifying costs and benefits through systems thinking and mapping; (2) analyzing the climate context using historical and projected data; (3) quantifying and monetizing these costs and benefits; (4) identifying financing structures; and (5) communicating the results.
• Systems thinking is presented as a critical prerequisite for NbS, described as a "discipline for seeing wholes" and a framework for understanding "interrelationships rather than things" to grasp the wider context of a project.
• To ensure a robust quantitative analysis, the guide recommends using three specific scenarios: a nature-based solution scenario, a "grey/built solution" designed for similar benefits to allow for comparison, and a "Business as usual" scenario where no interventions are implemented.
• The integration of CBA into the project lifecycle varies by stage: preliminary CBA occurs during 'Identification' to assess feasibility, detailed CBA is used in 'Formulation' to evaluate economic viability, and retrospective CBA is used during 'Evaluation & Audit' to measure actual benefits.
• Financing for NbS can be achieved through a combination of public and private investments, grants, subsidies, and other innovative financial instruments.

APA

International Institute for Sustainable Development (n.d.). Unpacking Methods for Integrated Assessments of Nature-Based Solutions. https://www.iisd.org/system/files/2025-04/integrated-assessments-nature-based-solutions-guidance.pdf

Chicago

International Institute for Sustainable Development. Unpacking Methods for Integrated Assessments of Nature-Based Solutions. n.d. https://www.iisd.org/system/files/2025-04/integrated-assessments-nature-based-solutions-guidance.pdf.

Wikipedia

{{cite report |author=International Institute for Sustainable Development |title=Unpacking Methods for Integrated Assessments of Nature-Based Solutions |url=https://www.iisd.org/system/files/2025-04/integrated-assessments-nature-based-solutions-guidance.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{internationalinstituteforsustainabledevelopmentndunpacking, author = {{International Institute for Sustainable Development}}, title = {{Unpacking Methods for Integrated Assessments of Nature-Based Solutions}}, institution = {International Institute for Sustainable Development}, url = {https://www.iisd.org/system/files/2025-04/integrated-assessments-nature-based-solutions-guidance.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }