The biological and physical limits of the planet, the threshold from which the Earth ceases to be a safe and habitable place for human life, are being overcome by the alterations caused by man. Resource overexploitation and its impacts are straining the Earth’s ability to cope (resilience) and continue to provide life support and essential environmental services. The result is that “human beings are incurring colossal risks” that compromise their future and that of all beings living on Earth, according to a study published in the journal Nature.
Scientists are making the first major attempt to objectify the safe and fair limits of the Earth system for some of the biological and physical processes and systems that regulate it. But not only do they assess the state of planetary health, they also take into account the dimension of justice; that is to say, the conditions that avoid the consequences and significant damage of this situation on human populations are used as a criterion.
In this sense, they claim that incorporating the criterion of justice in the definition of planetary boundaries “is not a political option”, but there is “overwhelming evidence that an approach of justice and equity is essential for planetary stability â€, since “we cannot have a safe planet in biophysical terms if there is no justiceâ€, emphasizes Joyeeta Gupta, co-author, professor of Environment and Development at the University of Amsterdam.
The so-called Earth Commission, made up of 40 scientists, has quantified the limits that are considered safe and fair for the preservation of climate, biodiversity, fresh water masses, nutrient cycles and the presence of pollutant aerosols in the atmosphere; and concludes that most of these indicators have been exceeded.
For example, the fair and safe limit for the climate, set at a temperature increase of 1°C above pre-industrial temperature levels, has already been exceeded, as tens of millions of people are already being harmed by the change climatic And the same is happening with the limits set to protect nature (that between 50% and 60% of the surface of the world’s ecosystems are not altered), since between 45% and 50% of these areas are already undergoing alteration and they do not fully fulfill the environmental services.
Human activities are also changing more than 34% of the world’s river flow, while 47% of the world’s groundwater surface is overexploited. Unacceptable amounts of nutrients (nitrogen and phosphorus) are released that contaminate the waters due to the excessive use of fertilizers; and the pollution indicator for ultrafine particles is also exceeded.
“The results are quite worrying. Unless there is a timely transformation, it is highly likely that critical points of irreversible change will be passed and, consequently, a widespread impact on human well-being will be inevitable. Avoiding this scenario is crucial if we want to guarantee a safe and fair future for current and future generations”, explains Joan Rockström, lead author.
Earth System Limits will be the basis for setting new science-based targets that can be adopted by cities, companies and countries to address the global systemic crises of climate change, biodiversity loss, overburden of nutrients, excessive use of water and air pollution.
