Quantifying Nature’s Value: Green Space Health Benefits Valued in Euros

A pioneering study has successfully developed and applied a sophisticated methodology to quantify and monetize the health benefits derived from nearby green and blue spaces, positioning this research at the forefront of natural capital accounting. This pilot study, conducted in the Flemish Region of Belgium, provides a robust framework for integrating ecosystem services into broader economic assessments by translating environmental attributes into tangible economic and health indicators. The research confirms that the availability of green-blue areas—which encompasses parks, agricultural land, private and public gardens, and surface waters—provides substantial health benefits to the population, which were estimated to be worth billions of Euros annually for Flanders in 2016. This work is particularly significant because it moves beyond simple ecological valuation, utilizing physical supply and use accounts to measure health impacts and then applying detailed monetary valuation techniques to assign economic value to these outcomes.

The core of the methodology lies in the use of physical supply and use accounts, which rely on a set of carefully selected dose-effect relationships. These relationships quantify how the availability of green space impacts seven specific indicators related to physical and mental health. The indicator used for green-blue areas is defined by the percentage of green-blue areas within specific radii—0.5, 1, and 3 kilometers—from a resident’s home, calculated using detailed 10m x 10m land-use maps of Flanders. The health impacts, which include mortality, cardiovascular diseases, diabetes, and depression, are weighted using Daly’s metric, the disability-adjusted life years (DALYs), and then aggregated to provide a comprehensive picture of the total health burden alleviated by the presence of nature.

The findings for 2016 revealed that the total health benefits attributable to the availability of green-blue areas for the entire Flemish population amounted to approximately 85,000 DALYs. This figure represents a substantial contribution, accounting for 27% of the estimated total burden of disease within Flanders for the seven selected diseases. Furthermore, the monetary valuation of these benefits was staggering, totaling 3 billion Euros per year for Flanders in 2016. When normalized, this translates to 464 Euros per inhabitant per year, equating to 1.3% of the regional Gross Domestic Product (GDP). This high percentage underscores the critical importance of green-blue areas not merely as aesthetic features, but as vital components of public health infrastructure with significant economic weight.

The monetary valuation component of the study is highly detailed, breaking down the total health benefits into three major components, consistent with World Health Organization (WHO) definitions. First, avoided medical costs, which include expenses for hospitalizations and patient medication, were estimated at 1.1 billion Euros. This category accounted for 36% of the total monetary value. Second, productivity gains from avoided absenteeism were valued based on labor market data from Belgium and specific disease statistics. This category was the largest contributor, accounting for 52% of the total monetary value. Third, welfare gains from increased life expectancy, valued using simulated exchange values derived from European willingness-to-pay (WTP) studies for the Value of a Life Year Lost (VOLY), accounted for 12% of the total monetary value. This comprehensive approach ensures consistency with national accounting standards, such as the exchange value methodology of national accounts.

The study methodology acknowledges inherent limitations, which are crucial for the interpretation and future application of the accounts. A primary limitation is the simplification of the green space indicator, which is currently based on the percentage of green-blue land use within a radius, rather than differentiating between ecosystem types, quality, accessibility, or specific use patterns. While the indicator is broad, encompassing parks, agriculture, and informal green areas, the researchers note that a more nuanced indicator is required to capture the full spectrum of health benefits. Furthermore, the reliance on dose-effect relationships derived from meta-analyses and studies in other regions, such as the Netherlands, introduces uncertainty. The authors explicitly state that the available dose-response functions are linear, which may not fully capture the non-linear health benefits expected in areas with very low green space availability.

The physical accounts utilize prevalence data for diseases, such as cardiovascular mortality, diabetes, and mental illnesses, translated into DALYs based on expected healthy life years. For instance, prevalence data for cardiovascular mortality were sourced from the Flemish Agency for Public Health, while data for mental illnesses were based on a six-yearly survey. The monetary accounts, however, face greater data scarcity, particularly regarding productivity loss and welfare losses due to suffering. For cardiovascular mortality, life years lost are valued using simulated exchange values from WTP surveys, a method necessitated by the lack of direct market prices for suffering. The study highlights that while the first two components (medical costs and productivity loss) are valued using market prices, the third component relies on these simulated exchange values, which inherently results in a lower valuation compared to some literature estimates.

Looking forward, the research identifies several critical priorities for potential users of these natural capital accounts, including environmental and health agencies. The primary recommendation is the development of advanced indicators that can measure daily exposure and engagement with green areas, moving beyond simple land-use shares. This would allow for the testing of non-linear dose-effect relationships and the differentiation of benefits based on the quality of the ecosystem—for example, comparing the health impact of a biodiverse area versus a monotonous one. In the short term, the authors suggest complementing these accounts with additional condition accounts to track the evolution of green-blue area quality and use over time, thereby addressing the challenges posed by urban sprawl and fragmented landscapes in regions like Flanders.

In conclusion, this research provides a powerful demonstration of how natural capital accounting can be extended to include physical and monetary health outcomes of urban green spaces. By successfully building physical supply and use accounts and corresponding monetary accounts, the study offers a vital tool for policy-makers. The results clearly demonstrate the economic importance of nearby green-blue areas, especially in the context of preventative healthcare and the mitigation of absenteeism, which contributes significantly to economic growth. Although the methodology is recognized as a crucial first step, its inherent limitations—such as the scope of covered health indicators and the simplification of exposure metrics—underscore the need for continuous, systematic health impact studies to refine these accounts and better serve the needs of vulnerable populations and future urban planning initiatives.

Subject of Research: Natural capital accounting valuation of health benefits from urban green and blue spaces.

Article Title: Valuation of health benefits of green-blue areas for the purpose of ecosystem accounting: a pilot in Flanders, Belgium

Article References: De Nocker, L., Liekens, I., Beckx, C., & Broekx, S. (2023). Valuation of health benefits of green-blue areas for the purpose of ecosystem accounting: a pilot in Flanders, Belgium. One Ecosystem, 8, Article e87713. https://doi.org/10.3897/oneeco.8.e87713

Image Credits: AI Generated

DOI: 10.3897/oneeco.8.e87713

Keywords: Natural Capital Accounting, Ecosystem Services, Public Health, Green Infrastructure, Natural Capital, Economic Valuation, Flanders, Sustainability, Valuation, health, benefits, green-blue