Nhe United Nations defines habitat (from the Latin habitare=to live) in relation to human settlements, places where, in their ideal state, ¿people possess a place where they find peace and dignity, without economic or social barriers. But habitat can be defined in different ways. In the field of ecology, it is the space in which a biological population can reside and reproduce in such a way as to ensure the perpetuation of its presence on the planet.

Unlike humans, other animals have very different requirements for their habitat, depending on needs related to temperature, humidity, availability of a certain food, etc.

At summary, a habitat is a place with the appropriate conditions for an organism or an animal or plant community to live and reproduce. These conditions are not static, since organisms can modify their habitat, which can lead to changes that force them to adapt to a new environment.

In the case of man, his habitat must be considered on a large scale, as it is found in the most diverse geographical locations and has the capacity to transform it. Think of global climate change (largely due to man according to the IPCC or Intergovernmental Panel on Climate Change), the destruction of the habitats of other species, the abundance of invasive species, the transformation Genetics of the species themselves¿ These changes also affect man, who increasingly simplifies his own habitat by taking cultures and technology to places where other human beings maintain a ¿better preserved¿ habitat.

Some simplify the concept of habitat by considering only the number of people it can house. However, different cultures have developed their model so that this maximum is very different in different places. Also the location of civilizations in the geographical sense must be considered when trying to find that ideal issue . It could be said that man is trying to distance himself from the traditional natural factors that determine his own habitat, using advances that no other animal has achieved.

The United Nations, in its dedication to ensuring that people have a place where they can find peace and dignity, without economic or social barriers", works to improve living conditions and work, and considers the possibility of being fed, protected and safe as a minimum. Are we heading in that direction?

We do not seem to be complying with nature's rules in this basic aspect for our survival. In the slogans used year after year on World Habitat Day, the protagonists are the cities, since it is a fact that the human population has "decided" that "its habitat" should preferably have this structure. If this is so, let us work so that they recover the minimum conditions for man to approach the ecological rule that guarantees his existence with that peace and dignity mentioned in the United Nations.

Let us make cities clean spaces, without pollution, with environments where children, young people, adults and the elderly can develop a variety of activities safely, in proximity to nature, and where the quality of life of all people has a minimum in relation to health, food, the possibilities of work and leisure, the social inclusion of the entire population and the recognition of individual and collective identity. It is true that some cities seem to be moving in this direction, in a kind of "green cities" competition. Let us hope that this is not only political.

Let us put the laws of nature before particular, ideological or partisan interests, also in the case of our species.