Study: The boundaries of the Earth have already been crossed

The International Climate Research Team believes that a safe and just life for all people on earth is not possible anymore. Almost all boundaries were crossed – but there are also criticisms of the study.

The state of the Earth and the well-being of mankind are closely linked. This is the starting point for the Earth Committee, an international association of scientists. They have now named the safe and fair boundaries of the Earth system and put them in numbers. Ha Stady They were published in the journal “Nature”.

If only the planet was in good shape, so be it A safe and just life for all possible people and other species. And not only today, but also for future generations. According to the research team led by the Director of the Potsdam Institute for Climate Impact Research (PIK), Johan Rockström, this situation can only exist if the limits of the planet’s resilience are not exceeded in eight basic areas.

It relates to global warming, the state and functions of ecosystems, the availability of surface and ground water, air pollution and the environment with pollutants, nitrogen and phosphorus. The study is based on scientific findings from the past few years and computer modeling.

Seven of the eight limits have already been crossed

According to Rockstrom and his team, the problem with this is that seven of the eight limits have already been crossed. However, biodiversity loss or global warming can no longer be reversed, which means: according to researchers, a safe and just life is no longer possible for many people on Earth today and in the future.

The concept of “planetary boundaries”

A few years ago, Rockstrom and his colleagues developed the concept of a “planetary boundary.” This defines the limits that must not be crossed if life on Earth is to be possible in the long term. These are not quite identical to the limits now defined, but they are quite consistent.

The theory behind it: For each of these areas, such as global warming, ocean acidification or biodiversity loss, there is a limit, called a tipping point, that must not be crossed. However, this can only be determined afterwards, that is, only after it has been achieved. The problem: Once you pass these tipping points, according to the researchers, there’s no going back.

Or, as Rockstrom put it two years ago in the Netflix documentary Breaking Boundaries: “Once Greenland thaws, nobody knows how to freeze it again.” And once several tipping points are passed, according to Rockström’s theory, others will soon follow – like dominoes.

A new study pushes boundaries

Aspects of “fairness” and “security” are now being added to the question of what the Earth can withstand in terms of man-made physical, chemical and environmental damage. This narrows the boundaries of what is still acceptable. Example: Even if global warming could be stopped at 1.5 degrees, that is, at the limit that is still considered scientifically plausible, this would only prevent the worst effects of climate change.

The poorest countries are particularly hard hit

However, in many parts of the world many people die even then, for example through loss of water, food and living space. According to the researchers, the poorest countries that could have contributed the least to climate change will be the most affected. Only if global warming was stopped at less than 1 degree, according to the team, could this evolution have at least slowed. And this, according to one of the results of the study, is just a limit that has already been broken and will make it impossible for many people on Earth to live safely in the future. In other countries, especially wealthier ones, the effects remained manageable.

Not everyone agrees

In first reactions, Rockström and colleagues’ concept received much approval from fellow researchers. Above all, the inclusion of the justice aspect is generally welcome.

Johannes Emmerling, from the European Institute of Economics and Environment in Milan, RFF-CMCC, told Science Media Center: “Overall, the study is unfortunately a wake-up call for politicians, in a number of areas where we risk losing control over the Earth’s fundamental subsystems – perhaps irreversibly.” – to lose it.

But there are also criticisms, for example from Henrique Pereira, head of the Biodiversity and Nature Conservation Research Group at the German Center for Integrative Biodiversity Research in Halle-Jena-Leipzig. “My main criticism of the concept is that these limits are not really set by science, but are instead influenced by science. That is, all limits are based on expert judgment of permissible risks and permissible outcomes, but another group of experts might come up with different numbers for limits.”

In addition, Kathryn Bonning-Gess, director of the Senckenberg Center for Biodiversity and Climate Research, adds that it is not certain that there are irreversible tipping points across the board. “Meanwhile, for biodiversity, it is becoming clear that these tipping points are unlikely to exist. When we lose biodiversity, there does not seem to be a safe zone. On the contrary, with the loss of all species, we seem to be losing ecosystem functions.” , sometimes more, sometimes less. Above all, with every species lost, the strength and stability of ecosystems is affected.”