The concept of Planetary Boundaries (PB) is a scientific framework developed by Johan Rockström and a team of international scientists. It defines the limits within which humanity can operate without jeopardizing the stability of Earth's systems. This approach focuses on analyzing nine critical processes that maintain planetary balance, such as climate change, biosphere integrity, and biogeochemical cycles. The framework emphasizes the importance of keeping Earth within conditions similar to the Holocene—a stable climatic period that enabled human development—and the urgency of taking action to prevent crossing these limits, which could trigger catastrophic global consequences.

The PB framework identifies nine key processes that sustain the Earth's stability, including climate change, biogeochemical cycles, biodiversity, ocean acidification, and water resource management. These define the thresholds within which humanity can function without disrupting planetary equilibrium.

Exceeding these boundaries—six of which have already been crossed, including climate change, biogeochemical flows, and biosphere degradation—could unleash a chain reaction of negative impacts, endangering the planet's stability and human survival.

The PB framework also highlights additional factors critical to maintaining Earth’s stability, such as:

• Effects of simultaneous breaches: violating multiple boundaries at once can trigger cascading feedback loops, amplifying global risks and reducing the resilience of essential ecosystems.
• Interconnection between climate change and the biosphere: climate change and biosphere integrity are deeply interconnected, with risks that could cause irreversible ecological transformations, such as the loss of rainforests or shifts in terrestrial biomes.
• Need for planetary governance: rethinking global governance is vital to ensure fair and sustainable management of natural resources by integrating Planetary Boundaries into international policies.
• Connection to the economy: planetary Boundaries align with economic theories like Kate Raworth's Doughnut Economics, which advocates for a sustainable economic model that respects both ecological and social limits.
• Continuous monitoring: regularly updating Planetary Boundaries analyses and developing advanced monitoring models are essential to manage cumulative violations and prevent irreversible damage.

The study stresses the urgency of global cooperation to restore planetary boundaries and foster a sustainable future. Kate Raworth's Doughnut Economics, which suggests an economic model respecting ecological ceilings and social foundations, aligns seamlessly with the Planetary Boundaries concept.

According to this theory, the economy should operate within a "planetary ceiling" to avoid harming the environment and a "social floor" to ensure human well-being.

Furthermore, the concept of environmental justice, as highlighted by Regg3, is essential to guarantee equitable access to natural resources for all, without exceeding critical ecological limits.

The connection between PB and Regg3 underscores the importance of inclusive and responsible governance to ensure both social and environmental sustainability, aiming for a "safe operating space" for humanity. The analysis calls for a revision of global policies and improved governance to tackle planetary challenges and maintain the ecological balance necessary for the planet's future.