
The economist identifies nine environmental thresholds that should not be exceeded in order to avoid further natural degradation that jeopardizes the health of the Planet even more: climate change, biodiversity loss, ocean acidification, land conversion, freshwater withdrawals, nitrogen and phosphorus loading, chemical pollution, air pollution and ozone layer depletion. What are the limits of the Doughnut model in order to prosper? To achieve this, it proposes transforming governance systems, making these regenerative and distributive instead of finite and egotistical. This change of paradigm proposes shifting from an economic model of constant growth measured by Gross Domestic Product (GDP) and realizing that, in the end, economic prosperity depends on human and natural wellbeing. Both circumferences coincide with the United Nations Sustainable Development Goals (SDG). In the middle would be the doughnut, understood as the space in which humanity can progress if the planet's boundaries are respected. It receives this name because it is visually represented by two doughnut-shaped discs: the one in the center is the social foundation, which includes basic fundamental rights, and the outer ring is the ecological ceiling, which cannot be exceeded if we are to guarantee the prosperity of humanity. The theory of the Doughnut formula is a change of economic model as a response to humanity's major challenge: eradicating global poverty all within the means of the planet's limited natural resources.

What is the doughnut theory or the theory of Doughnut economics? In both, she proposes a new humanist economic model, a tool which many cities worldwide are starting to use. The term 'Doughnut Economics' was first coined by the British economist Kate Raworth in a report published in Oxfam in 2012 and which she subsequently continued to develop in her book 'Doughnut Economics: seven ways to think like a 21st century economist'.
