How many biophysical / planetary boundaries does Earth has?
Back in 2009, in an article published in Nature ("A safe operating space for humanity"), a team of researchers led by environmental scientist Johan Rockström investigated.
In the researchers’ view, planet-altering human activities could be assembled into nine groups. Thresholds were calculated then for most of them, beyond which the result could spell danger for the planet and its people. The original concept, according to some critics, was that the study lacked environmental justice and equity. It needed to take into account the fact that everyone, especially the most vulnerable, has an absolute right to water, food, energy and health, alongside the right to a clean environment.
Yesterday, May 31, 2023, Nature published an updated article by Rockström, together with sustainability scientist Steven Lade and a team of researchers. And when addressing that gap, incorporating justice alongside the biophysical boundaries, the outcome was not good. Earth has pushed past seven out of eight scientifically established safety limits and into “the danger zone”:
1) climate
2) natural ecosystem area
3) ecosystem functional integrity
4) surface water
5) groundwater
6) nitrogen
7) phosphorus
8) erosols
"Earth is ‘really quite sick now’ and in danger zone in nearly all ecological ways" according the the headline of AP News.
The Nature article ends like this: "Researchers vary widely in their views on how this question should be addressed ... we urged scientists representing these different approaches to forge more channels of communication between them. The paper we are publishing represents one such opportunity. If the findings are anything to go by, there is no time to lose."
Click at the image below "Planetary boundaries reboot" (source: J. Rockström et al.) for the full article.
To conclude, the concept of “planetary boundaries” was introduced 15 years ago to identify major Earth systems that were at risk of instability because of human activity. the red lines indicate a limit to what is ‘safe’ for the planet. In the updated concept, the green space was added to represents the threshold that is both safe for the planet and protects the world’s most vulnerable populations (‘safe and just’). The Earth-shaped icons show how, in seven of eight cases, thresholds for a safe and just world have already been crossed.
