On water, climate and natural areas, the Earth is already beyond the safe limits: this is announced by an international scientific commission composed of over 40 researchers from all over the world, which has traced the boundaries beyond which the Earth will cease to be a safe environment for humanity. The analysis also includes for the first time parameters such as justice and equity, in the same way as those that assess the well-being of ecosystems and biophysical processes of our planet. According to the study, published in the journal Nature, the data are worrying: many of these limits considered safe have already been exceeded and for others, such as those relating to air pollution, it is not long away. This poses serious threats to the stability of the Earth, ecosystems and their vital contribution to humanity.
"Justice is a necessity for the lives of human beings on Earth: overwhelming evidence shows that a fair and equitable approach is essential for planetary stability," comments Joyeeta Gupta of the University of Amsterdam and the Delft Institute for Water Education, one of the authors of the study led by Johan Rockström, of the German Institute for Climate Impact Research in Potsdam. "It is therefore necessary to define the right objectives – says Gupta – to prevent significant damage and ensure access to resources".
The researchers estimated the safest limits for climate, biodiversity, water use and different types of pollution: most of these are already violated, particularly in the Middle East, Southwest Asia and Eastern Europe.
For example, the climate limit assessed as safest, set at 1 degree above pre-industrial temperature levels, has been exceeded, since we are already at 1.2 degrees above that threshold.
At least 50-60% of intact natural areas globally and 20-25% per square kilometer locally have also been crossed: intact natural ecosystems have already fallen below 45-50% and, locally, more than two-thirds of the soil does not respect the threshold considered fair and safe. Furthermore, the alteration of water flow due to human activities has reached 34%, where the limit is set at 20%, while the withdrawal of water from aquifers has reached dangerous levels for 47% of global water resources. And the same can be said for the level of fertilizers poured into waterways and reservoirs, broken for different substances.
"The results of our analysis are quite worrying: within the factors analyzed, different boundaries, on a global and local scale, have already been crossed," says Rockström. "This means that unless timely transformation occurs, it is very likely that irreversible tipping points and widespread impacts on human well-being will be inevitable. Avoiding this scenario – continues the researcher – is fundamental if we want to guarantee a safe and just future for current and future generations".