Humanity is an integral part of a wider ecosystem, made up of many other living beings, animals and plants, as well as inorganic elements (such as CO2) that "coexist" in a complex and, in some respects, precarious balance.

Every man, woman and child (like every living being) has an impact on this ecosystem.

When that impact exceeds the environment's capacity to absorb it, it must be reduced.

In nature there are feedback mechanisms that tend to bring living beings and their ecosystem into balance: thanks to its ingenuity and abilities, humanity has managed to escape these mechanisms, growing in number and in its impact on the environment to the point of substantially altering the ecosystem, and ultimately endangering its own survival and that of other living species.

This may lead to scenarios that must be averted.

This problem outweighs every other that society faces today or has ever faced in the past, whether social, economic or of any other kind: every other consideration must give way to solving the environmental problem (within the limits of a society's ability to absorb and manage the consequences that necessarily follow from this approach), not least because in many cases the environmental problem is itself the root cause of problems of a different kind (migration, for example).

Environmental sustainability can only come from reducing resource consumption, as the Club of Rome showed 50 years ago in its report "The Limits to Growth".

Bringing human activities back into balance with the ecosystem is not compatible with endless growth in the production and consumption of goods and services, and therefore inevitably requires a radical change in today's economic system and social organisation, which are inextricably based on the assumption of growth.

It is not reasonable to rely, as an act of faith, on innovation and science as a deus ex machina able, at some undefined point in the future, to solve every problem in this respect.

If this change is not properly prepared for and managed, it may cause imbalances and social disorder potentially capable of bringing about the collapse of the State and of the other organisations traditionally responsible for maintaining social order.

Since such a collapse is probably inevitable, even regardless of the environmental crisis, because of the progressive depletion of available energy wealth (the falling average EROEI, Energy Return on Energy Invested, of the energy sources currently available), it is better to prepare for it and manage it than to suffer it.