The analysis distinguishes weak sustainability, which assumes that the functions of natural capital can be substituted by manufactured, social or human capital, from strong sustainability, which treats the economy as a subsystem of the environment and allows only limited substitution. Weak-sustainability measures commonly use monetary valuation to calculate environmentally adjusted wealth. By contrast, strong sustainability requires physical accounts to identify the condition of critical natural capital or the cost of maintaining its integrity. The authors contend that environmental degradation makes the substitutability assumptions of weak sustainability difficult to justify.

SEEA is an international statistical standard for statistics describing interactions between the economy and the environment. Its key documents remain neutral about which sustainability approach countries choose, but both approaches can begin with physical natural-capital accounts. The review finds that the SEEA Ecosystem Accounting manual, published in 2021, makes the strongest contribution to strong sustainability through ecosystem condition accounts. These accounts use reference values to rescale variables representing abiotic, biotic and landscape features into ecosystem-condition indicators.

Identifying critical natural capital requires both a judgement about which elements are critical and a reference value specifying the condition at which their functions must be preserved. Proposed criticality criteria include ecological importance, social importance, economic importance and threat level. Although researchers have mapped assets associated with important ecosystem services, including a study of assets associated with 90% of 14 ecosystem services, the review says such work does not solve the broader identification problem. Environmental functions may arise from interactions among elements of natural capital, meaning that the characteristics and processes of the whole stock may need to be safeguarded rather than individual assets alone.

The central limitation identified in the review is that SEEA Ecosystem Accounting provides guidance on reference conditions and values but does not itself determine the necessary thresholds. Reference conditions can represent optimal, sustainable or contemporary ecosystem states, and the manual recommends methods drawing on historical or recent observations, modelling, statistical analysis, prescribed levels and expert judgment. Without suitable references, an indicator may show whether ecosystem condition is improving or deteriorating without establishing whether conditions remain compatible with the maintenance of ecosystem functions.

Implementation also remains uneven. Forty-one countries had compiled ecosystem accounts of various types, nearly three times the number recorded in 2017, but extent accounts remained more common than condition accounts in Europe. Data on condition were scarcer than data on extent and tended to favour abiotic variables. A review cited by the paper also found that the use of reference values in condition accounts was not standard practice. The authors identify the greater development of condition accounts and more explicit reference values as needed to give SEEA greater policy relevance while preserving the standard’s neutrality between weak and strong sustainability.

Other established initiatives can provide reference values. The Planetary Boundaries framework compares Earth-system indicators with safe levels, while the Environmental Sustainability Gap framework uses science-based environmental standards to assess whether natural-capital functions are threatened. The latter operates mainly at the national scale, matching the scale of most SEEA accounts, and its standards fit the “prescribed levels” category described in SEEA. The review reports overlaps between standards used in a European Environmental Sustainability Gap case study and prescribed levels in some ecosystem-condition assessments. However, country pilots could not always be compared because they did not use identical standards.

SEEA also has substantial potential to support wider policy indicators. Reviews cited in the paper identified 40 SDG indicators that could be supported by SEEA, while another assessment identified 21 potentially fully aligned indicators and two with partial alignment. Of 45 indicators provisionally selected to monitor the GBF, 27 could be supported by SEEA. Nevertheless, neither the SDGs nor the GBF explicitly invokes strong sustainability or critical natural capital. A separate review of four institutional SDG indicator sets found that 9–20% addressed natural capital or its functions and that 0–34% had sustainability reference values, depending on the set. The authors therefore conclude that meeting the SDGs may contribute to strong sustainability, but the indicators generally do not measure it directly.

The review identifies three actions: making SEEA’s capacity to support both sustainability approaches more explicit in the Central Framework and thematic manuals; expanding ecosystem-condition accounts alongside extent accounts; and incorporating environmental standards into condition assessments. It also identifies reference values as a potential route for strengthening the post-2030 sustainable-development framework and biodiversity monitoring. The review is conceptual and comparative rather than a new implementation trial, and its recommendations remain constrained by incomplete ecosystem-condition data, inconsistent reference standards, context-dependent thresholds and the conceptual and practical difficulty of defining critical biodiversity conditions.

Subject of Research: A review of strong-sustainability indicators, SEEA accounting, the SDGs and the Global Biodiversity Framework

Article Title: Strong sustainability in the SEEA and the wider indicator landscape

Article References: Usubiaga-Liaño, A., Selomane, O., & Comte, A. (2025). Strong sustainability in the SEEA and the wider indicator landscape. One Ecosystem, 10, Article e141086. https://doi.org/10.3897/oneeco.10.e141086

Image Credits: AI Generated

DOI: 10.3897/oneeco.10.e141086

Keywords: SEEA, strong sustainability, natural capital, ecosystem accounting, reference values, environmental standards, Sustainable Development Goals, Global Biodiversity Framework, Planetary Boundaries, biodiversity, Strong, sustainability