Numbers That Matter: Simple Lessons for a Resilient Life!" Every number tells a story, and in this series, I dive into how those stories can build resilience. By diving into simple stats, we’ll learn how to stay grounded, find purpose, and build resilience in the face of change.
The Sustainable Development Index (SDI) is an alternative measure of sustainable development to Sustainable Development Goals Index (SDG Index), which I described in a series of three articles. SDI: Is a simpler, more direct metric that focuses on a few key indicators (life expectancy, education, income, CO₂ emissions, and material footprint). This clarity makes it easier to interpret and act upon. It is used as the key measure of sustainable development by Gapminder, one of my favourite source of quality statistical information.
The SDI evaluates how efficiently countries achieve human development within ecological limits. It adjusts the traditional Human Development Index (HDI)—which considers life expectancy, education, and income—by accounting for each nation's ecological footprint. This adjustment reflects the extent to which a country's consumption-based CO₂ emissions and material usage exceed sustainable levels. A destabilizing ecological impact, as defined in the SDI methodology, occurs when consumption patterns cannot be offset by sustainable practices, leading to the breach of planetary boundaries.
Income Levels and Sufficiency Thresholds
A particularly interesting aspect of the SDI is its consideration of income levels. The SDI sets $20,000 (2017 PPP) as the sufficiency threshold on the income index scale. This is the point above which additional income becomes unnecessary for achieving strong social outcomes, such as life expectancy, education, happiness, and gender equality.
Several countries demonstrate this principle effectively. According to 2019 data:
Costa Rica achieves a life expectancy that exceeds that of the US with 71% less income per capita ($18,500).
Georgia achieves education levels comparable to Austria with 74% less income per capita ($14,400).
This observation challenges the traditional narrative of perpetual economic growth as the ultimate measure of success. Countries with moderate incomes can achieve excellent social outcomes while maintaining lower ecological impacts.
Maximum Income and Ecological Limits
The SDI also identifies maximum income thresholds, beyond which sustainable development becomes unrealistic due to ecological destabilization:
GNI per capita above $60,000 has a highly destabilizing ecological impact.
GNI per capita above $75,000 is considered empirically incompatible with planetary boundaries.
The chart below illustrates the relationship between GNI and the income component of the SDI. It shows that once a country surpasses $20,000 GNI per capita, the income component of the SDI flattens. Inhabitants of wealthier countries are unlikely to experience significantly higher life satisfaction, even with increased income.
High-Income Nations and Ecological Impact
The relation between GNI and the SDI in 2022 is presented on the chart below.
A small group of countries exceeds the $75,000 threshold, including Ireland, Singapore, Qatar, and Luxembourg. In the broader group of nations with destabilizing ecological impacts (GNI above $60,000 , we find the United States, Switzerland, Denmark, Norway, Hong Kong, and the United Arab Emirates.
While these countries are often considered leaders in sustainable development, their levels of consumption generate negative environmental impacts that cannot be offset. Sustainable production, even in advanced economies, carries ecological costs. When consumption outpaces sustainable limits, the integrated impact remains negative.
This raises an important point: sustainability initiatives in high-income nations may be insufficient if consumption levels are not addressed. Circular economies, renewable energy, and technological efficiency are valuable tools but cannot fully compensate for excessive material usage and CO₂ emissions.
Lessons from Moderate-Income Countries
Given that income is so tightly coupled with ecological impact, it makes sense to look at nations that achieve high levels of human development with moderate levels of income as models to emulate in the process of designing more sustainable approaches to development
A very interesting group of countries falls into the range of $20,000 to $60,000 GNI per capita with SDI scores above 0.5. Notable examples include:
Developed nations such as France, the United Kingdom, and Italy.
Developing nations such as Poland, the Czech Republic, and Slovakia.
These countries demonstrate that prioritizing efficiency over consumption can lead to balanced and sustainable development. For example:
Investing in education and healthcare yields strong social outcomes without requiring excessively high income levels.
Encouraging smarter consumption through circular economy practices reduces ecological costs.
Conclusion
More evidence and perspectives are emerging that challenge the 20th-century growth-driven economy, which appears to have crossed its ecological limits. Principles such as circular economy, minimalism, and sustainability call for a rethinking of progress and development.
The SDI presents a controversial but thought-provoking picture of the current state of sustainable development. It highlights that after reaching a certain level of income and consumption, further economic growth does not necessarily improve quality of life and becomes ecologically unsustainable.
While aspiring economies often look to the richest nations as models, this may prove to be a trap rather than a destination. Instead, nations achieving strong human development within moderate income levels can provide a blueprint for sustainable progress.
Practical Questions
Should policymakers focus more on improving quality of life through healthcare, education, and equality instead of chasing endless economic growth?
How can high-income nations address excessive consumption patterns to mitigate their destabilizing ecological impacts?
Can moderate-income countries serve as models by balancing development and sustainability through smarter, resource-efficient methods?
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And again a strong topic, brave and to the point. Hoping more influential and in power people are aware of that issue... Thank you:-)