What sustainability means, and the limits it is measured against
Sustainability is the capacity of the biosphere and human civilisation to coexist, a term wider than any one of its parts. It is set against the Anthropocene, an age marked by one species' impact on the planet, and it is measured by frameworks that hold development against the planet's limits: the planetary boundaries, a country's development index against its ecological footprint, and the doughnut of a social foundation beneath an ecological ceiling.
What the term covers
Sustainability refers generally to the capacity for the biosphere and human civilisation to coexist. Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own demands. The original definition, in the Brundtland Report to the United Nations several decades ago, gives sustainability three pillars: ecological, economic and social.
Sustainability is a fairly wide and encompassing term, so climate action, gender equality, affordable and clean energy, responsible consumption and production, and industry, innovation and infrastructure are all correct answers to what it is. In a 2020 webinar poll that offered these five answers, attendees chose responsible consumption and production most and gender equality least.
The Anthropocene
By a 2020 account, the International Geological Society, which determines the planet's geological ages, had decided that the Holocene, in which humanity appeared, has given way to a new age, and was still determining when it began, around 200 or 50 years ago or so. It is called the Anthropocene, the age of the human species, because that species has had so massive an impact on the planet. Humanity has changed the planet so much that its traces, such as the amount of nuclear waste produced, the amount of mining, ocean acidification, artificial chemical elements and artificial species, will be detectable for hundreds of millions of years more, if not for the rest of the planet's existence.
The human population is healthier than ever before: life expectancy has increased and child mortality has decreased, owing not least to research and its results. There is far less poverty on the planet than there was before. Achieving this has meant exploiting the planet at an unprecedented rate, with often exponential curves in water use, energy use and fertiliser. On the current trajectory, humanity will be limited by the amount of food it needs to grow and by its demand for fresh water.
The planetary boundaries
Humanity operates within a set of planetary boundaries, of which climate change is only one. Treating climate as humanity's only environmental impact has been called carbon tunnel vision, while humanity also does much more to the planet in ocean and fresh water use, biodiversity and other boundaries. As of 2023, six of the boundaries had already been crossed. In one speaker's 2024 view, efforts on the environment must not focus only on carbon emissions but must also think about solutions for water, air and soil pollution.
Human development against ecological footprint
A 2020 plot of each country's United Nations Human Development Index, where higher is better, against its ecological footprint in hectares per person, where lower is better, shows that no country sits in the sweet spot of a high index with a low footprint. European countries sit high on the index, with pretty good education and low child mortality, and carry a sizeable footprint from energy consumption and waste; African countries on average sit lower on both the index and the footprint.
The term developing countries usually refers to the global south, but the economist Jeffrey Sachs, who helped define the Sustainable Development Goals, holds that every country is a developing country, because every country can and must improve in terms of sustainability. Arguably the same holds for corporations and organisations: all of them are developing, and none is really there yet.
Doughnut economics
Doughnut economics, developed by the economist Kate Raworth, is a simple representation of the social and planetary boundaries that underpin human well-being. It is a framework for sustainable development that balances the ecological boundaries of the planet with the social boundaries of humanity. At its centre is the minimum social foundation needed for a good life, such as enough water, enough food and enough jobs, and outside it is an environmental ceiling of critical natural thresholds that should not be exceeded, such as the amount of greenhouse gases in the atmosphere. The inner ring is the 12 social dimensions derived from the UN Sustainable Development Goals, below which no one should fall, and the outer ring is the nine planetary dimensions proposed by an international group of Earth-system scientists, the ecological ceiling that must not be overshot if humanity is to live within Earth's life-sustaining systems. The ring between them, which gives the framework its doughnut shape, is the safe and just space for humanity, inclusive and sustainable in its economic development. Improvements to one ecological or social dimension can positively affect the others.
By a 2021 account, humanity was overshooting nearly all of the planetary boundaries, while a substantial part of the world's population fell short of the social foundation. Global carbon dioxide levels, a control variable for climate change, were nearly 410 parts per million in 2019, considerably above the safe upper limit of 350 parts per million. The challenge is to bring humanity inside the doughnut, into its safe and just space. Global economic policy and models are at the heart of the environmental crisis and central to fixing it, and doughnut economics is a new way of economic thinking that could provide the radical changes needed to tackle the crisis. It is increasingly recognised that radical action is required if humanity is to continue to prosper, or even survive, as a species within a flourishing web of life.
Economic growth as a measure and a target
Economic growth, as a measure of productivity or success, is usually measured as gross domestic product (GDP). In one speaker's 2020 view, a growing number of critical voices within economics and beyond hold that GDP alone is a fairly poor measure, to be read with the Human Development Index, the ecological footprint and the growth of happiness rather than of material things. GDP measures only economic activity, so even cleaning up after ecological disasters contributes to it. In the same view, the doughnut principle is a middle ground. Good things such as knowledge, happiness and equality can grow, some of them endlessly, while others, such as consumption and resource footprint, cannot grow further, because that is not sustainable and the biosphere takes too much of a toll.
By a 2021 account, the prevailing mindset and priorities of governments and businesses did not align with the doughnut framework. Endless financial economic growth is a very commonly used target, although infinite growth is not possible in a system with finite resources such as the planet. For many businesses the primary goal is economic growth to satisfy short-term profits and shareholder return rather than improved human prosperity.
One view, put as an economic rather than a political statement, is that communism collapsed because it did not allow prices to tell the economic truth, and that capitalism in its currently existing form may well collapse if it does not allow prices to tell the ecological and social truth, such as what it costs to destroy nature or what it costs to leave people below a good level of development. The benefits ecosystems provide in supporting humans, such as carbon sequestration, have been described as ecosystem services and given a calculated monetary value. This has highlighted the importance of the natural world to human well-being, at the risk of reducing the living world to a price or asset on a balance sheet in a finance-centric economy.
The linear and the circular economy
The linear economy, described as take, make, use and dispose, is the norm, and it is incredibly wasteful of raw materials and finished products. Current degenerative, linear practices need to change to ones that are regenerative by design, restoring and renewing life cycles, and the circular economy is a system central to this. The circular economy aims to eradicate waste through careful design: the biological or technical components of a product are designed for disassembly and re-purposing with minimal energy, with high-quality resultant products, systems are run on renewable energy, and the waste product provides the raw material for a new process or product. Ideally, materials are reused in perpetuity. The circular economy has the potential to positively affect several boundaries of the doughnut, directly, such as by reducing pollution and freshwater withdrawals, and indirectly through knock-on effects in other ecological and social dimensions, as when reducing air pollution leads to healthier living conditions.
Regenerative design and the doughnut in practice
From her experience with multiple business leaders, Kate Raworth outlines five corporate target levels for sustainability, the responses of businesses to awareness of Earth's planetary boundaries. The ultimate solution for entering the doughnut is regenerative design, reconnecting with and giving back as much as possible to the natural world, so that the world is left better than it was found. One initiative that helps businesses achieve regenerative design is biomimicry, which looks to nature's systems to create more sustainable designs and products, from biodegradable detergents to factories that function like a forest. The Doughnut Economics Action Lab works with businesses, governments and communities worldwide to turn doughnut economics into action, for example through policy making, reframing economic narratives and systemic transformation. By 2021 organisations were using the EN-ROADS climate simulator, a prediction tool, to design scenarios that limit future global warming.
By 2021 a wide range of organisations were engaging with doughnut economics: two architects had won the Pritzker Architecture Prize for regenerating buildings rather than destroying and rebuilding them, businesses in clothing and retail were rethinking their corporate strategies in line with the framework, and cities such as Amsterdam were striving to bring themselves within the doughnut by protecting the environment and natural resources, reducing social exclusion and guaranteeing good living standards for all.