Today, May 18, is World Museum Day. A day to celebrate the rich diversity enjoyed by these institutions in Navarra. But also to explain to citizens why there are museums like ours, the Science Museum of the University of Navarra, dedicated to studying and preserving another diversity: the natural one, rich as few others.

Rarely does news about the conservation of natural diversity make the news. The preview broadcast last week of the upcoming report of the Intergovernmental Science and Policy Platform on Biodiversity and Ecosystem Services (IPBES), for rather grim reasons, just did.

Getting the details of the full report (1500 pages) will have to await publication in a few months, but for the first time, IPBES has gathered abundant evidence for a clear warning: that rich biodiversity of the planet we study is falling like never before.

Never in history have a million species been at risk of disappearing before the retirement of our grandchildren. The figure is estimated on the basis of "only" about one hundred thousand of the one and a half million known species (and another six or seven million that we do not know). These are the ones studied in the Red List of the International Union for Conservation of Nature (IUCN). Of these, a quarter are compromised (some, very much so).

Starting from 27,000 species and ending up with one million is an uncertain leap, but much less than turning two thousand respondents into twenty million voters. We cannot therefore expect that this million will remain at twenty thousand, just as we cannot expect that a poll that predicts one hundred deputies for a party will find that, after the polls, only two remain.

Two options remain with this estimate: either it is valid or it is not. Only with more data will we know if it is wrong by excess... or wrong by defect. For most species (more than half of them insects) we hardly know where they were discovered and almost nothing about their life. As scientists we face an insidious problem: the so-called "taxonomic impediment" which, among other things, reflects the growing lack of specialists in laboratories and science museums.

Science Museums are the repositories ofthe knowledge we have accumulated. Their collections are the tool necessary to compare what we have and what we had, and ooze data that allow us to calculate these forecasts. But if we do not correct the current crazy consumption of natural resources, they could end up being just the sad final file of Nature.

Nature is a living file from which species are disappearing every day before we even know they exist. Selfishly, the benefits that biodiversity (ecosystem services) could give us - such as, for example, deactivating toxins - will be ignored. Each species that disappears is one less option to defend us from a plague, cure a disease or provide sufficient resources to a still growing population.

Biodiversity change is natural because it evolves, and has been accompanied by a natural rate of extinction punctuated by five massive episodes over 400 million years. However, neither the speed nor the current direction of change is natural. This time it is we who, by changing the rules of the game of the planet by overexploiting other species or their habitats, are making the species we know and those we do not know disappear.

Ignorance of species means not being able to take measures to protect them, something necessary not only for the benefits they give us but also for their intrinsic value: each species is a unique form of life and we have no right to destroy it. By protecting them we protect ourselves; by blindly exploiting them we exploit ourselves to the point of blindness. Acting carelessly with nature is an unacceptable risk and is morally unjust, because nature belongs to our children and not to us.

Our maintenance as a species is possible by consuming the interest produced by natural capital. But the figures of the IPBES report are clear: our current "success" (the development and the goods we enjoy) is based on spending our own capital, without alternative investment. It's a bad recipe, and you don't need to be an economist to know it.

We know that nature does not make unsecured loans. It didn't do it to dinosaurs last time.