Humanity must be guardian of the Earth to avoid collapse – 05/31/2023 – Environment

If humanity wants to prevent its actions from throwing the systems that support life on Earth out of balance, and at the same time guarantee decent living conditions for all people, it will need to adopt a strict set of “speed limits” in the way how we use natural resources, says a new study.

The bad news is that several of these planetary “road signs” are already being ignored at the global or local level, says the survey, which has just been published in the scientific journal Nature.

“Science is clearly showing that human actions are destabilizing the Earth-system, and the only way is for us to become guardians of this system”, summarizes one of the research coordinators, the Swede Johan Rockström, from the Institute for Research on Climate Impacts from Potsdam (Germany).

In a paper published in 2009, Rockström and his colleagues were responsible for the original formulation of the concept of planetary boundaries. According to this idea, there would be a natural limitation on the functioning of components of the planet, such as the water cycle, the flow of essential nutrients for plants and biodiversity.

If these components were exploited beyond their normal functioning capacity, the environmental stability on which living beings depend to survive could suffer severe disturbances, with potentially catastrophic impacts even for human beings.

In the new study, the Swedish researcher and colleagues such as Joyeeta Gupta of the University of Amsterdam and Dahe Qin of the Chinese Academy of Sciences expanded the concept to formulate planetary boundaries that are both “safe” for human life and “fair” ” for different societies on a planetary scale.

“We sought to create common units of measurement that would unite the views of the natural sciences and the social sciences on the problem”, explained Rockström in an online press conference. “Our point of view is that there is no security [ambiental] without justice”, summed up Gupta.

The list of borders of the “Earth-system” defended by the specialists includes elements such as climate, the presence of natural ecosystems, the availability of fresh water on the surface and in the subsoil, the nutrients nitrogen and phosphorus (present, for example, in industrial fertilizers ) and aerosols (roughly speaking, small particles suspended in the atmosphere).

To define planetary borders that are not only safe but also fair for all, the researchers considered three main principles. From a human point of view, they emphasize intergenerational justice (ie, between generations, so that the grandchildren and great-grandchildren of the current population do not have their lives seriously jeopardized by selfish decisions made now). There is also intragenerational justice (within the same generation), between different countries, communities and individuals.

But the researchers also highlight interspecies justice, considering that the interests of human beings cannot be the only ones weighing in the balance of planetary limits. The team says that “human exceptionalism” must be rejected for this purpose to be achieved.

In most cases, the limits considered “fair” and “safe” meet, but there are exceptions. In the case of the climate crisis, for example, the team considered that a maximum increase in the average global temperature of 1.5 degrees Celsius (the same level established as desirable by the Paris Agreement, a global pact on the subject) would be “safe”.

But very negative manifestations of climate change are already being felt with the temperature increase currently detected, of 1.2 degrees Celsius, mainly affecting the most vulnerable. Hence the consideration that the “fair” limit would be only 1 degree Celsius. As there is no prospect of undoing climate damage in future generations, this indicates the need for compensation for those most affected today.

The other limits have almost all been breached, but would, in theory, be easier to revert than the climatic ones. This is the case of the area with well-preserved nature reserves, for example. The researchers calculate that at least somewhere between 50% and 60% of the planet’s land area should have this function. However, between 45% and 50% of the global territory is already occupied by human activities.

The exception, according to the group’s calculations, is the presence of polluting aerosols (derived mainly from the burning of fuels and biomass). Current aerosol production is about a third of what would be the planetary limit.

For Rockström, part of the importance of quantifying all these variables is finding clear ways to implement them not only at the global level but also at local scales, taking into account regions, cities and even companies, because many of the most important changes will have to happen in local level.