Planetary boundaries
The SBTN may still be in a planning phase, but it is drawing on an established foundation of science. One of the guiding principles for the SBTN is the nine planetary boundaries, a concept developed by 28 international researchers, including Johan Rockström of the Stockholm Resilience Centre and Will Steffen from the Australian National University, to describe certain thresholds that have the potential to destabilize the world. The concept was introduced in an article in Nature in 2009.
The nine boundaries — climate change, biosphere integrity, land-system change, freshwater use, biogeochemical use, ocean acidification, atmospheric aerosol loading, stratospheric ozone depletion, and chemical pollution and the release of novel entities — identify various Earth system processes, each containing thresholds for safe operating limits. Stay within the thresholds, and life can still thrive; cross the thresholds, and the Earth can shift into a dangerous new state, the research says.
For instance, it suggests that we have already passed the safe threshold for climate change when atmospheric carbon dioxide levels surpassed 390 parts per million (ppm), moving the world into a zone of uncertainty. Thresholds have also been exceeded for land use, the biogeochemical flows of phosphorus and nitrogen, and biosphere integrity due to accelerating rate of biodiversity loss and mass extinctions, according to the Stockholm Resilience Centre.
“We know if we go beyond that boundary, then we’re walking into a minefield, and we could step on a mine at any point,” Owen Gaffney, director of international media and strategy at the Stockholm Resilience Centre, told Mongabay in an interview. “And we have no idea where it is, and that’s the risk we’re taking.”
On the other hand, Earth system processes such as ocean acidity are still within safe operating limits, although they are quickly moving toward the direction of not being safe, according to the study. The nine boundaries are also tightly connected, Gaffney says, meaning that the crossing of one threshold could result in the crossing of more.
“For example, when you start reducing biodiversity of a forest, then you’re reducing its resilience,” he said. “And then, small changes could tip it into a new state — a rain forest could become a savanna-type state. And then that savanna-type state may not store as much carbon, [so there is] more carbon in the atmosphere, so then you’re having a knock-on effect on the climate boundary. Then with more carbon dioxide in the atmosphere, you get more ocean acidification.”
How can the concept of planetary boundaries help businesses? By providing a “priority list” of planetary issues, Gaffney says.
“I think the power of the boundaries is that it provides that list, and secondly provides a quantification,” he said. “You can’t manage what you can’t measure.”
Using science as a guiding principle, the SBTN is working to inform companies on how they can set science-based targets that will help protect all parts of nature, and to operate within the realm of planetary limits. For instance, the SBTN is drawing on the work of the Science Based Targets initiative, a partnership between the Carbon Disclosure Project (CDP), the United Nations Global Compact (UNGC), World Resources Institute (WRI) and WWF, to help companies set targets to cut their carbon emissions. So far, over 1,000 have committed to do so.
“Our job is to translate that in ways that can be actionable for companies and cities, so that they can operationalize and set targets that ensure that they’re doing at least enough, or their fair share … to stop the loss of nature, to drive toward the equitable net zero carbon nature-positive future that … is needed in the environmental space,” Billman said.