Two reports have renewed the debate over whether nations should stop prioritizing economic growth.
In June, the Global Justice Report, published by a research organization called the World Inequality Lab, called for a rebalancing of income and wealth, and for the richest countries to accept lower growth, to solve planet-wide problems such as environmental degradation and climate change1.
In May, a United Nations group of economists, the High-Level Expert Group on Beyond GDP, published a set of recommendations for moving beyond gross domestic product (GDP)2. The report called on nations to manage their economies around a dashboard of indicators of sustainable well-being, and not just GDP.
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Yet, this focus on growth risks asking the wrong question. The central issue is not simply whether economies should become richer faster or slower, or how general well-being can be measured, but whether governments are leaving behind more or less wealth for future generations.
Sustainability is fundamentally a matter of justice3: what one generation owes to the next. The debate around how this can be achieved has given rise to tensions (see Nature 655, 547; 2026). The Global Justice Report largely frames justice in the context of space: between countries and between wealthy people and those living in poverty. Approaches to managing sustainability within planetary boundaries — to avoid breaching global limits of natural resources and systems — seek justice across periods of time, between present and future generations.
Here, I clarify what justice between generations means, how it applies to economics and how inclusive national accounts for produced, human and natural capital offer a way forwards.
To understand concepts of wealth and justice, it’s worth looking back at the history of economics, as I did when researching for my book, The Inclusive Wealth of Nations (2026). It was timed to coincide with the 250th anniversary of one of the most influential books in economics: Adam Smith’s An Inquiry into the Nature and Causes of the Wealth of Nations (1776).
In that work, Smith defined a nation’s wealth not in terms of money but as capital — machines, buildings, land and the “acquired and useful abilities of all inhabitants and members of the society”. Economists still follow this approach.
Smith also outlined how enabling justice is an essential role of the state. But it was in his earlier book, The Theory of Moral Sentiments (1759), that Smith set out his views on justice more fully. One aspect that has been underappreciated is how an individual’s actions affect others.
Smith could not accept that the actions of one person, through ignorance or otherwise, should be allowed to hold back another. “Though his own happiness may be of more importance to him than that of all the world besides,” he wrote, “to every other person it is of no more consequence than that of any other man.”
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He outlined a framework for judging someone’s actions on the basis of the perception of an ‘impartial spectator’, an imagined, well-informed observer who assesses whether the actions are worthy of praise or blame. Crucially, to “disturb the happiness” of others because it stands in the way of our own would be intolerable to the impartial spectator.
Although Smith was writing about the moral conduct of his own society, the impartial spectator can be imagined as a future generation judging whether a previous one has acted as a responsible custodian of the wealth it inherited.
Smith did not use the terms ‘sustainability’ or ‘intergenerational justice’, but his analysis points to the underlying problem: a nation becomes wealthy not by consuming its inheritance but by preserving and enlarging the stocks of capital on which future prosperity depends. For example, investment in roads, bridges and other infrastructure increases the capacity to produce goods and services available to people today and to those who inherit it, provided it is maintained.
He thought it was wrong to allow the present generation to benefit while passing the burden to those that followed. One example is national debt. He objected to governments borrowing to “relieve the present exigency” while leaving the “future liberation of the public revenue … to the care of posterity”.
Therefore, existing capital stock is the fruit of the “frugality” of our forebears. And decisions about whether to maintain or run down capital stocks affect not only prosperity today but also the opportunities available to future generations.
Intergenerational justice
Since the 1970s, economists have understood the concept of sustainability through a lens of intergenerational justice. As well as building on Smith’s framework, the concept expands on political philosopher John Rawls’s idea of ‘just savings’, namely that “each generation must not only preserve the gains of culture and civilization, and maintain intact those just institutions that have been established, but it must also put aside in each period of time a suitable amount of real capital accumulation”4.
Such investments might be made, Rawls suggested, in machinery for manufacturing or in learning and education. He gave no guidance on how that should be achieved, but he provided two ways of thinking about the problem.
Investment into capital assets, such as bridges, roads and other infrastructure, can increase a nation’s capacity to produce goods and services.Credit: Han Suyuan/China News Service/VCG/Getty
One considered maximizing well-being for all: what if subsequent generations were always richer? It would be unfair for poorer generations to save more than future, wealthier ones, because they would be sacrificing more of their own well-being for the benefit of people who are expected to be better off.
The second was expressed through the veil of ignorance: what if we do not know which generation we belong to? To avoid favouring our own, each generation should follow the same principle of saving, with the amount saved depending on its circumstances. In this way, each generation, bar the first, benefits from the savings of those before it.
These ideas were developed further by two Nobel laureates, Kenneth Arrow and Robert Solow. Arrow applied them to conventional measures of capital, such as machinery, buildings and infrastructure5. Solow broadened them to also include exhaustible resources, such as oil, gas and mineral deposits6. Their work raised another question: could one generation justly deplete natural resources if it compensated future generations by investing in other forms of capital?
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Economist John Hartwick came to the conclusion that reinvesting all revenues from exhaustible resources into other forms of capital would be one way to achieve just savings7. Solow applied this idea to the UK North Sea oil boom in the 1980s, arguing that the nation, unlike countries such as Norway, had squandered its natural resources by not reinvesting the revenues in other forms of capital8.
Economists Partha Dasgupta and Amartya Sen extended this thinking to sustainable development9,10. Dasgupta defined sustainability in terms of the productive base of an economy: each generation should leave its successor at least as large a base as it inherited, so that the opportunities for well-being available to future generations are no worse than its own. Sen defined it as preserving — and, if possible, expanding — the capabilities and freedoms of the current generation without compromising those of future ones.
Therefore, today’s focus on maintenance of capital to preserve the capabilities of future generations is essentially the argument that Smith made 250 years ago.
Preserving tomorrow’s capabilities
The next question for economists is how to measure just savings. These are not captured by GDP, which measures only a nation’s level of production of goods and services. As I’ve argued along with my colleague Matthias Beck, a management scholar at University College Cork, Ireland, just savings can be tracked through ‘inclusive wealth’, a measure that focuses on three different forms of capital — produced (manufactured), natural (environmental) and human (skills and knowledge). By contrast, GDP is generated by combining these capitals, along with knowledge, while institutions, such as legal systems and political organizations, shape how effectively resources are allocated.
In the context of planetary boundaries and global catastrophic risks, inclusive wealth is a better measure of economic health than is conventional GDP, because it reveals what is happening to the underlying asset base. It tells us whether today’s growth is being achieved by building wealth or by running down the natural, human and produced capital on which future prosperity depends11.
If the current generation runs down our natural capital, then future generations will not have access to the same capabilities. And, if the capital stock is not maintained — if roads and bridges are in a state of disrepair, for example — then future generations will have less capital at their disposal.
