Motivation: Structural evenness is a widely adopted essential concept in both the natural and social sciences, such as the biodiversity in ecology and the wealth gap in economics. However, the role of structural evenness in sustainable development — the blueprint for human society — has rarely been explored, despite the Sustainable Development Goals (SDGs) emphasizing the holistic fulfillment of all 17 goals. Based on our previous research experiences in ecology, we developed the SDG progress evenness index (ES) to quantify the progress differences among 17 goals, while integrating ES with the widely adopted mean SDG index score (MIS) to build up a novel two-dimensional SDG assessment framework (Liu et al. Natl. Sci. Rev., 2021, doi: 10.1093/nsr/nwaa238; Liu et al. The Innovation, 2024, doi: 10.1016/j.xinn.2024.100573). Furthermore, following this assessment framework, we investigated the global effects of progress towards SDGs on human subjective well-being (SWB) — another well-established metric that has guided human activities and social development for thousands of years.

Key Findings: The decoupling dependence of SWB on SDG evenness and per capita GDP, as countries proceed towards achieving SDGs (Figure 1). In countries with poorly-progressed SDGs, SDG evenness is the key factor shaping the SWB, while in countries with well-progressed SDGs, SWB strongly depends on per capita GDP.

Figure 1 The similar decoupling relationships between SWB and SDG evenness (left) and plant productivity and biodiversity (right; Wang et al. 2022)

Implications:

• Science: resource redundancy in sustainable development. The decoupling relationship between SDG evenness and SWB suggests that the more even allocation of resources in multiple aspects of human society (resource redundancy) is generally vital in stressful instead of non-stressful environments, which is in line with the well-established organizational slack theory in economics (Sharfman et al., Acad. Manag. Rev., 1988). The underlying mechanism can be ascribed to Liebig's Law of Minimum: the more shortcomings in sustainable development, the lower the SWB is, highlighting the importance of SDGs from the individual human perspective. On the other hand, the neutral or negative effects of SDG evenness might be explained by the potential trade-offs between environmental protection and economic development. Countries approaching fulfillment of SDGs have abundant resources to meet essential human needs, while their underperforming goals generally relate to the environment (for example, SDGs 12, 13, and 14). Elevating SDG evenness is generally associated with improving progress on lagging goals such as environmental conditions, thus enhancing SWB. However, such emphases on environmental protection might slow down or impede economic growth, the most vital determinant of SWB, thus neutralizing or even overriding the positive effects of improving environmental quality.
• Policy: bottom-up strategies. Advances in science, social equality and press freedom might help stimulate people's desire for SDGs (Figure 2), which are paramount and effective in promoting sustainable development. For instance, through more fundamental research and public outreach programs, people could be warned of the negative outcomes of unsustainable development from individual perspectives and thus reattach their SWB to SDGs.

Figure 2 Social governance factors promote the synergy between SDG evenness and SWB

• Future perspective: For the first time, our study uncovers the long-neglected subjective control factor in global sustainable development. How the current SDG framework can better convert its achievements into SWB outcomes constitutes a vital frontier in sustainable research, involving not only economic incentives and technological innovations but also broad social, educational and cultural shifts. Moreover, this unimodal SWB-SDG evenness relationship resembles the well-established hump-backed plant productivity-biodiversity relationship in ecology (some references: Grime, Nature, 1973, doi: 10.1038/242344a0; Fraser et al. Science, doi: 10.1126/science.aab3916; Wang et al. Natl. Sci. Rev., 2022, doi: 10.1093/nsr/nwac165; Figure 1), underscoring the importance of structural evenness in the broader disciplines, including biology, ecology, economics, sustainability and social sciences.

Link: https://doi.org/10.1038/s41893-024-01270-5