Study: Six of Nine Planetary Boundaries Crossed Massive School Closures Due to Violence in Central and West Africa

Human exploitation of planet Earth poses increasing risks. According to a study, six of the nine so-called planetary limits have already been exceeded, in some cases significantly.

“The Earth is a patient that is not doing well,” said co-author Johan Rockström, director of the Potsdam Institute for Climate Impact Research (PIK), in a statement from the institute. “We don’t know how long we can cross critical boundaries in this way before the effects lead to irreversible changes and damage.”

Crossing a planetary boundary marks a critical threshold for significantly increasing risks, explains first author Katherine Richardson from the University of Copenhagen: “We can imagine the Earth as a human body and the planetary boundaries as a form of blood pressure. A blood pressure above 120/80 does not mean that there is an immediate risk of a heart attack, but it does increase the risk.

Safe range

The planetary boundaries, which are intended to define a safe space in which humanity can operate, were first defined in 2009. These include nine sub-areas, such as freshwater use, the function of the biosphere, climate and the aerosol pollution of the atmosphere. Now the international research team led by Rockström and Richardson analyzed the status of all nine systems.

The safe range has been significantly exceeded in terms of global warming and the integrity of the biosphere, the team writes in the journal ‘Science Advances’, pointing to species extinction and habitat destruction. “In addition to climate change, the functionality of the biosphere is the second pillar of the stability of our planet,” says co-author Wolfgang Lucht from PIK. “And just like with the climate, we are currently destabilizing this pillar.”

The line has also been crossed in terms of the introduction of new substances into the environment – ​​that is, the ingress of man-made chemical compounds such as microplastics, pesticides or nuclear waste. The situation when it comes to freshwater consumption is not so critical, but here too, it is said, the planetary boundary has been crossed.

Hope for improvement

Global particle pollution in the atmosphere is currently still within the safe range, although this limit is regularly exceeded in some regions, such as South Asia. According to the researchers’ definition, ocean acidification is just in the green zone, as is ozone depletion in the upper atmosphere.

Precisely because of this development, the team hopes that other problems will also improve: in the 1990s, the depletion of the ozone layer exceeded the planetary limit. “But thanks to global initiatives achieved through the Montreal Protocol, this limit is currently no longer exceeded,” Richardson points out.

To reassess planetary boundaries, the research team used current research and also simulated Earth’s development using models of the Earth system and biosphere for a few hundred years into the future. They used the phase between the last ice age and the beginning of the industrial revolution as a basis for comparison.

Limit global warming

If a limit is exceeded, there are still ways to improve the situation, the team points out, using the example of global warming for reforestation. Would humanity succeed in limiting the CO2 content of the atmosphere to 450 parts per million (ppm) – currently 417 – and also limit the coverage of boreal and tropical forests to as much as 60 percent of the original forest cover? A decrease in it could significantly slow global warming.

“The simulation then suggests an average temperature increase across the country of 1.4 degrees by the year 2100,” the report said. However, many climate researchers believe that achieving the target of limiting global warming to 1.5 degrees Celsius above pre-industrial levels is no longer realistic. (sda/dpa)