What is the difference between nature and biodiversity?
The difference is very simple: nature covers all existing systems—created at the same time as the Earth—whereas biodiversity is the part of nature that is alive, born on a mineral substrate, in an earlier geodiversity. Biodiversity is not limited to a sole inventory of species: above and beyond the number of butterflies in a field or bacteria on a surface, it covers all of the relationships between living beings and also with their environment. This biodiversity is universal, it stretches from forests to seabeds all the way to alluvial plains, but is also found in wines, cheeses, and within the core of each one of us. We cannot live without the biodiversity that composes us, feeds us, dresses us, and lives within us, because the human body is made up of as many bacteria as of human cells.
Does this idea of biodiversity allow us to better understand ecological issues?
The problem is how to better measure our impact on biodiversity if we are not aware of all of the species that inhabit our planet. New bacteria are constantly appearing, species disappear every day without us having noticed their existence; change is constant and life adores that. If disturbances generate diversity, they should nevertheless not be too frequent, so as to allow species to settle. Nature is not balanced but tends more toward a harmony of interdependent systems. Another problem is to know which species “deserve” to be protected, whether they all have the same importance in maintaining this harmony or whether they have a function or value as a “cornerstone.” The general public is ready to donate a lot to save whales, giraffes, and other remarkable animals, whereas a tick or a beetle will not enjoy the same success. Therefore, it is above all environments that should be protected.
How can we recognize the value of the services provided by nature, which are a matter of common property but considered as free?
Developed at the end of the nineteenth century, the idea of “ecosystem services” has really caught on thanks to the Millennium Ecosystem Assessment, an event that gathered together almost 1,300 scientists who sought to diagnose the state of the planet’s ecosystems at the time of our entry into the third millennium. This idea raises the question of the differences between value, cost, and price. We are able to say that the horn of the white rhinoceros is worth this amount, or that we would be prepared to pay this or that price to save the redtail parrotfish. But the value of the services that nature provides to humankind is based on a completely different calculation. I am thinking of the purification of water through rocks, of the production of oxygen by phytoplankton, or even of pollination. We are aware of a little over 2 million living species—recorded in museums—and at least 250,000 of them are pollinators, including many insects, birds, and bats. In China, a country that has been heavily affected by man’s activities, farmers—and in particular women—are forced to pollinate by hand. The annual cost that this would represent for the world in the event of a total disappearance of bees would be close to 180 billion dollars in terms of salaries. Objectively, the degradation of our environment costs us dearly, including on a financial level.
What relationship can humanity, which is now principally urban, maintain with this biodiversity?
Sedenterization has generated demographic growth. As a consequence, agriculture and animal breeding have ceased to accompany man in his new living conditions. There were once humans without agriculture, now humanity can no longer exist without it. The development of agriculture has profoundly modified ecosystems. When one considers the impact of mankind on our planet, one must also consider the impact of pets and field crops. Twelve thousand years ago the sum of human beings—5 million—and domestic mammals represented 0.1 percent of the totality of the mass of mammals on the planet: today they represent 90 percent.
The destruction of biodiversity has been caused by different factors: the destruction of ecosystems—Paris was once a forest; generalized pollution—Man even manages to pollute spaces where he is not present, like the Arctic or the oceans; over-exploitation—fishing and deforestation have become too intensive to allow nature to recover and renew itself; dissemination—our movements bring exotic and invasive species along with them; and the climate, this changing climate, in the face of which one would have to be of terribly bad faith to not assume one’s own responsibility. It is as much our own wellbeing as that of the planet that we should seek to protect. The Earth existed long before us, and will survive long after we are gone. It is very important to understand that we do not exist alongside nature, but are very much a part of it. Every time we attack it, we are attacking ourselves. It is truly stupid.
The question then becomes: how can the restrictions of this system be used to modify it? I really like the term resiliency, but in order to be resilient one must exist, and so, first, resist. It is up to us to go and find in nature the ally that she has always been, so as to draw upon factors of resistance. Leonardo da Vinci said “take lessons from Nature, our future is there.” We have always looked to nature—through biomimicry or bio-inspiration—for solutions to our problems, because nature has encountered and resolved them before us. But we should above all break with our arrogance and our greed. Nature is parsimonious, it is constantly optimizing, while man wants only to maximize. A handful manage to do this, but at the cost of plunging the others into misery. Nevertheless, I have no faith in the answers provided by demiurges who advocate the use of particles to reduce the greenhouse effect in the atmosphere. It could be technically possible, but once the process has been initiated, the carbon dioxide will begin to accumulate and it will be impossible to stop it.
Pushing back nature’s limits, increasing our abilities or becoming immortal (if we succeed!): so many desires that are only of concern to the richest part of humanity. The systematic imbalance and the inequalities generated will result in the rise of new fundamentalisms and terrorisms. We can see this currently with the war in Syria. Its outbreak in 2011 came in the wake of the twelve worst years of drought that the fertile crescent had seen in over three centuries. The disproportion between the wealth accumulated, the financialization of the economy, and the impoverishment of the majority of the planet is not “sustainable.” We have to return to a state of harmony with nature, curbing this race toward profit, seeking well-being rather than wealth. This is the reason why I strongly believe in civil society and in a dialog that involves all citizens and scientists.
How can we explain the return of the “wild” in a city like Paris? In what way can the architect and urban planning accompany it?
Cities have always played host to a particular form of biodiversity. Pests, rats, or cockroaches, these “wild urbanized species” populated them first. Since the seventies, we have seen a return of birds to cities, because of their verticality—anything that flies has better access to smaller refuges, to the ecological niche that this morphology provides—with predators being rare and much higher temperatures in winter in cities in milder zones than in the surrounding nature. This urban biodiversity can be observed in Paris with the return of Peregrine falcons around the bell tower of Notre Dame, and badgers and foxes in the Père-Lachaise cemetery, or the acclimatization of parakeets that have escaped from aviaries. All we need now is for wolves to return to the capital! With regard to plant life, of the 7,000 known species in France, 1,000 have been recorded in Paris, not counting exotic horticultural or spontaneous plants. This is massive.
With the Museum of Natural History we have created a science program for city dwellers called “Sauvages de ma rue” (The wild things of my street). Many thousands of people living in cities participate by informing us of the presence of a new plant in their garden or an encounter with a migrating bird. In this way, they help us to inventory and carry out very precise monitoring of urban biodiversity. The city is an important sector of the participatory sciences, and allowing each one of us to participate in the development and sharing of knowledge seems essential to me.
Architecture and urban planning also play essential roles in the creation of places for life and wellbeing. During the first fortnight of August 2003, the year of the heatwave, almost 15,000 people died in France. Between the concrete streets and the parks of Paris, we measured almost eight degrees of difference in temperature. Bringing “greenery” back to the city is absolutely fundamental, all the more so in the wake of an article that appeared in The Lancet, saying that access to a green space at the heart of a large city has reduced the number of illnesses in the populations of cities over the last thirty years. Not forgetting that these types of spaces also reduce social inequalities.
Architecture, reconnecting with nature, also allows the installation of vegetable gardens on roofs and grass-covered facades, homes for many hundreds of pollinating species. And the honey produced in Paris is of exceptionally high quality! It is obviously not a question of providing for all of the nutritional needs of city dwellers, but urban agriculture does allow us to re-engage with a lost wellbeing. The only downside is the often uneven access to these gardens. But the fact that architects tend to become, if not environmentalists, at least ecologists is ultimately a very good thing.