We Have Crossed Six of Nine Planetary Boundaries!

SCIENCE FICTIONFEATURED

10/25/20223 min lesen

The planetary boundary framework applies the latest scientific understanding of how the Earth system functions to define “safe operating spaces” for humanity, offering limits on how much human activity can affect these critical processes without triggering irreversible changes

For over 3 billion years, the interaction between life (represented by the planetary boundary called “Biosphere Integrity”) and climate has controlled the overall environmental conditions on Earth. Human activities, such as altering land use, redirecting water in rivers and soil, introducing synthetic chemicals into the open environment, and releasing greenhouse gases into the atmosphere, are disrupting these interactions.

Respecting and maintaining the interactions within the Earth system, similar to how they’ve functioned for the past ~12,000 years, is critical in preventing human activities from triggering dramatic changes in Earth’s conditions. Such changes could potentially reduce the Earth’s ability to support modern civilizations.

Nine “planetary boundaries” represent the key components of the planet that regulate its stability and habitability for humans. The extent to which these boundaries are exceeded is due to human-induced activities. The planetary boundary framework applies the latest scientific understanding of how the Earth system functions to define “safe operating spaces” for humanity, offering limits on how much human activity can affect these critical processes without triggering irreversible changes.

A recently published study offers, for the first time, specific criteria for each of these boundaries. It reveals that six out of the nine boundaries have been crossed, with breaches growing worse for all boundaries except for the depletion of the ozone layer. The study highlights that focusing solely on climate is insufficient. It emphasizes the urgent need to develop Earth system models that accurately reflect the interactions between boundaries, especially between Climate and Biosphere Integrity.

Published in Science Advances, the study represents the third update of this framework, led by twenty-nine scientists from eight different countries.

The Earth's "Blood Pressure" is Too High!

Katherine Richardson, professor at the Globe Institute, University of Copenhagen, and lead author of the research, emphasizes the concerning trend of increasing boundary breaches:

“Crossing six boundaries doesn’t mean we are doomed to disaster, but it’s a clear warning sign. We can liken it to your body’s blood pressure. Having a reading above 120/80 doesn’t guarantee a heart attack, but it increases the risk, which is why we try to lower it. We need to reduce the pressure on these six planetary boundaries for the well-being of ourselves and our children.”

A key takeaway from the study is that more focus must be placed on the interactions between boundaries. Johan Rockström, director of the Potsdam Institute for Climate Impact Research (PIK) and the original proponent of the framework in 2009, says:

“If we want to protect the Earth system from irreversible damage, focusing on human-induced climate change alone is not enough.”

Wolfgang Lucht, head of PIK’s Earth System Analysis division, adds:

“Alongside climate change, biosphere integrity is the second fundamental pillar of our planet's stability. Our research shows that reducing global warming and preserving a functional biosphere for the future must go hand in hand.”

Biomass Use is Impacting Biodiversity!

The need to respect the Land-Use Change boundary is increasingly tied to the growing global use of biomass as an alternative to coal, oil, and gas. Biomass is the product of the photosynthesis process, where plants convert sunlight into energy usable by other living organisms, thereby supporting biodiversity. Richardson explains:

“Our study shows that humans are appropriating the equivalent of about 30% of the energy that was available to support biodiversity before the Industrial Revolution. Naturally, removing such a significant portion of energy that would otherwise be available to nature likely contributes to biodiversity loss. This is why we propose that Human Appropriation of Net Primary Production (HANPP), i.e., biomass use, be adopted as one of two metrics to assess human impacts on biodiversity.”

Better Earth System Models Are Needed!

Johan Rockström states:

“A world that develops within the boundaries defined by science is the only way to manage our current situation, which involves escalating and potentially destructive risks on a planetary scale. We already know that the Paris Agreement has adopted the planetary boundary of limiting global warming to 1.5°C. Similarly, when the 2022 Montreal-Kunming COP15 agreed to halt and reverse biodiversity loss on land and in the ocean, the world acknowledged another planetary boundary related to biodiversity.”

However, our study shows this is not enough. If we truly want to secure prosperity and equity for everyone on Earth, the science of Planetary Boundaries offers an 'action guide.' This guide extends beyond climate and requires systematic efforts in new Earth system modeling and analysis to preserve, enhance, and rebuild planetary resilience.

Katherine Richardson concludes:

“I hope this new study serves as a wake-up call for many and increases international focus on limiting our impacts on the planet to preserve the Earth conditions that have allowed human societies to thrive.”

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