What are the ultimate limits of our planet? Scientists now have the answers

There is no Planet B. The now familiar refrain of climate activists reflects the urgency of mitigating the worst impacts of climate change. If we fail, the only planet we have to call home could become hostile to human existence.

The world’s largest network of sustainability scientists is behind the Earth Commission (EC) – a convening of scientists from across the world who have drawn up a range of Earth system planetary boundaries to quantify the limits that ensure a future for all life on Earth.

The Earth Commission announced that the science journal Nature is publishing its first integrated manuscript, detailing "Safe and Just Earth System Boundaries for the Global Commons".

These eight boundaries – an update to the Planetary Boundaries framework, which took 40 scientists four years to define – now integrate 'justice' in the same units as 'safety'.

"This marks a step change in understanding the Earth’s finite limits and how to protect people and the planet," the EC said.

The new work will lay a new foundation upon which science-based targets for more than climate can be developed. These will help hold policy-makers and business leaders accountable to maintain a safe and just operating environment.

Paul Polman, former CEO of Unilever and co-author of the book Net Positive: How Courageous Companies Thrive By Giving More Than They Take, says: "In practice, for CEOs, taking this people-centric approach is going to mean more ambitious and urgent targets and actions. Following the research, as we should, will mean setting the bar higher, but ultimately setting it where it belongs, with human beings at the heart of our collective efforts to build a better and safer future for all.”

Gim Huay Neo, Head of the Centre for Nature and Climate at the World Economic Forum, says:

“This science is critically important for business. It connects climate to nature, freshwater, clean air and other global commons and defines what is needed to secure our collective future. It highlights how the current trajectory is untenable for the global economy and society.

"Businesses will face interacting crises and escalating risks in their operations and supply chains, which will destroy value. This new research will become the scientific underpinning for how businesses can and should build strategy, set targets and implement action to mitigate the risks and exercise leadership to safeguard the conditions for their continued success.”

The threats posed by climate change, biodiversity loss and the degradation of the oceans is reflected in the World Economic Forum’s Global Risks Report, 2023.

An index of the most serious risks to global stability over the next 10 years is dominated by environmental factors.

The top four risks in the report are climate-related, and there are six environmental risks in total. They include the failure to mitigate climate change, natural disasters and extreme weather events, as well as the loss of biodiversity leading to the collapse of entire ecosystems.

The urgent need to set new boundaries reflects the impact of human activity on fragile planetary systems. If we take biodiversity loss as an example, a look at the data from the Living Planet Report 2020 tells the story of ecosystems in rapid decline.

As the illustration above shows, every region of the world has recorded a dramatic loss of nature and wildlife. In Europe, a quarter of all biodiversity has been lost. In Latin America and the Caribbean, the loss of reptile and fish species has seen biodiversity decline by a staggering 94% since 1970.

The Earth Commission’s work to build new environmental thresholds goes well beyond the targets designed to limit global temperature rises, says Professor Dahe Qin, Director of the Academic Committee of Chinese Academy of Science and co-chair of the EC.

“To combat climate change, nations have agreed to limit global warming to well below 2 degrees celsius. What we lack are comparable objectives for other key environmental components. The Earth Commission will fill this critical gap.”

To focus its approach on the largest risk areas, the EC has divided its operations into five working groups:

This group maps direct human interactions with oceans, biosphere systems and the Earth’s atmosphere, with the aim of developing targets for a planet that is stable and safe for humans and other terrestrial life.

Scientists in this group are exploring the scale and integrity of ecosystems needed to keep the planet within safe and just parameters. These parameters will guide the formulation of clear targets.

This group works to analyse how changes in nutrients such as nitrogen, phosphorus and carbon can undermine the stability and resilience of the Earth, for example by polluting water systems.

Experts within this group focus on the social and economic drivers of changes to the Earth’s natural systems. The group looks into the governance that will be required to deliver the required transformations to protect the planet.

This group is all about putting the recommendations of the Earth Commision into practice. It will translate the various assessments into science-based targets to assist governments, businesses and city authorities in implementing planet-positive actions.

Without urgent and systemic action at a global scale, the threat to our planet and its ability to support life will grow exponentially. The Global Risks Report 2023 sets out the urgency to act and the consequences of failing to do so.

The report says: “Without significant policy change or investment, the interplay between climate change impacts, biodiversity loss, food security and natural resource consumption will accelerate ecosystem collapse, threaten food supplies and livelihoods in climate-vulnerable economies, amplify the impacts of natural disasters, and limit further progress on climate mitigation.”