By Anders Lorenzen

The Potsdam Institute for Climate Impact Research (PIK), founded in 1992, has identified that six of the world’s planetary boundaries have been crossed.

The Institute is led by Prof Johan Rockström who specialises in planetary boundaries.

A team of international scientists have documented a detailed analysis of planetary resilience and mapped out all of the world’s nine boundary processes which define a safe operating space for humanity. This is the first time this exercise has been carried out.

The boundaries range from climate change to the biosphere and deforestation, and from pollutants & plastic to nitrogen cycles and freshwater. The scientists have concluded that out of those nine boundaries, six have now been crossed, and the pressure in all those boundary processes is increasing prompting fears we could be entering a territory of irreversible tipping points.

Like a sick patient

Commenting on the research, Rockström, who was co-author of the report, said “This update on planetary boundaries clearly depicts a patient that is unwell, as pressure on the planet increases and vital boundaries are being transgressed. We don’t know how long we can keep breaching these key boundaries before combined pressures lead to irreversible change and harm.”

The planetary boundaries framework was first introduced in 2009. This is the first update since then that provides a complete check-up of all the nine processes and systems which determine the stability and resilience of the planet. While it must be underlined that boundary transgressions are not necessarily equivalent to drastic changes happening overnight, they do mark a critical threshold for increasing risk, the report notes.

Katherine Richardson from the University of Copenhagen, a lead author of the report, further explains: “We can think of Earth as a human body, and the planetary boundaries as blood pressure. Over 120/80 does not indicate a certain heart attack but it does raise the risk and, therefore, we work to reduce blood pressure. The boundary for ozone depletion, for example, while not transgressed globally, was headed for increasing regional transgressions. Though it still is exceeded today over Antarctica, it is now slowly recovering – thanks to global initiatives, catalysed by the Montreal Protocol.”

Covers more than climate change

The report states that this is just the second update of planetary boundaries since the frame was established.  For the first time, it also includes entity boundaries which have been quantified as well as evidence that they have been crossed, for example, showing the accumulation of all novel chemical compounds that humans have created such as micro-plastics, pesticides and nuclear waste. The researchers add that for the first time, there’s now also scientific evidence that makes it possible to quantify the boundary of atmospheric aerosol loading. In addition, the freshwater boundary now addresses both green water (held in soil, plants, farms, forests etc.) and blue water (rivers, lakes etc) – both boundaries have been crossed. 

In another first, a control variable for the biosphere integrity was introduced – revealing evidence for another crossed boundary which in fact has been crossed since the late 19th century, when global agriculture and forestry saw major expansions. The researchers underline that in fact, planetary resilience goes well beyond climate change.

Rockström adds the concluding remarks: “Science and the world at large are really concerned about the rising signs of dwindling planetary resilience, manifested by the transgression of planetary boundaries, which brings us closer to tipping points and closes the window to have any chance of holding the 1.5°C planetary climate boundary. At the same time, it is a true breakthrough that we now have a scientifically quantified safe space for humanity on Earth, providing a guide for action and the first full picture of our planet’s capacity to buffer stress. Having this knowledge at hand marks an important step for more systematic efforts to protect, recover and rebuild planetary resilience.”  

A full explanation of the planetary boundaries can be found here.