One hundred and fifty experts from IPBES1 published an alarming report on the state of biodiversity on 6 May. Associate Professor at Sorbonne University and a member of the Center for Ecology and Conservation Sciences2, Jean-Baptiste Mihoub is part of the Geo Bon3 expert group, the linchpin of IPBES. It brings to light the undersides of this sixth mass extinction.
"Of the 10 to 20 million species that exist on the planet between 500,000 and 1 million are threatened with extinction in the coming decades, which represents 50 percent of known species," says Jean-Baptiste Mihoub.
If there are disparities by species and region, all are declining. Since the 1970s, 60 percent of vertebrate populations have disappeared, and up to 83 percent for freshwater species. In Germany, researchers have seen an 85 percent decrease in insect biomass in just 30 years. More worryingly, species that are not yet considered threatened with extinction have declined by more than 30 percent. And some formerly common tend to collapse, as for example hedgehogs that have lost 90 percent of their population in the UK since the 1950s.
"We are at the dawn of a sixth extinction that jeopardizes the balance and the functioning of ecosystems, of which man is an integral part," says Jean-Baptiste Mihoub. What makes us dizzy is the magnitude and speed of this decline."
The five great causes of this sixth extinction, all of human origin
"The causes of this biodiversity crisis are well known to scientists," specifies Jean-Baptiste Mihoub.
The fragmentation and destruction of habitats is the first threat to biodiversity due to urbanization, agriculture, deforestation or destruction of the seabed. Overexploitation of species is the second leading cause of biodiversity decline. Climate change, the first effects of which are already visible, may cause profound ecological upheavals in the next few years. The fourth cause, the pollution of water, soil and air, but also light and sound pollution directly affect some species. Finally, the introduction of invasive alien species that disrupt the functioning of local ecosystems is a fifth threat to biodiversity.
"We can say that the magnitude this disappearance is directly related to human activities. A species that represents a tiny part of life is capable of endangering the rest of biodiversity, "says the scientist.
Humans account for only 0.01 percent of the living biomass4 on Earth, while plants account for 80 percent, bacteria 12 percent and fungi 2 percent. Yet human biomass today represents almost 10 times the biomass of wild mammals and 30 times that of wild birds.
"This omnipresence of the human population on the planet, its exponential growth and the globalized impact of its activities on the Earth, what we call the Anthropocene, directly threatens biodiversity," explains Jean-Baptiste Mihoub.
Research and education to act in favor of biodiversity
For Jean-Baptiste Mihoub, "we must be realistic, but not fatalistic. If the report is alarming, the biggest mistake would be to do nothing and resign yourself.” According to him, we need to look deeply into our way of life. "The ecological transition will really start only when societies start to influence more than just governments and industry."
"As scientists," he says, "we need to put forward key figures and scenarios that, without being reductive, can become concrete and credible targets for political decisions. What has been done in recent years on CO2 emissions should also be done for biodiversity."
For this to happen, Mihoub says it is necessary to create global observation systems of biodiversity by sharing data collected locally.
"We lack data globally. Our models are not robust enough. We know there will be points of no return, but we are not able to predict when, how and on what scale, "he says.
An open-science actor, Jean-Baptiste Mihoub works within a network of other international researchers to standardize biodiversity measurements and data globally, as did climate scientists in the IPCC (the Intergovernmental Panel on Climate Change). Having a global vision of global biodiversity will, in his opinion, make it possible to better understand the mechanisms at work, to measure their effects and therefore to be better able to predict them.
"As professor-researchers, we have a responsibility to inform the general public but also to educate more and more students, including non-biologists, on this issue of biodiversity with the university’s scientific knowledge." insists Jean-Baptiste Mihoub.
At Sorbonne University, academic programs have evolved in this direction. For the past two years, a transdisciplinary minor "Environment" has provided students with in-depth education on major issues such as climate, energy, biodiversity, urbanization and agricultural transition. In order to educate students for a broader vision, the environmental issue is approached in a multidisciplinary and collaborative way through scientific as well as legal, political, ethical and philosophical angles.
1 Created in 2012, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) brings together more than 130 member states. At the interface between political decision-making and biodiversity research, it publishes scientific assessments on the state of knowledge about biodiversity, ecosystems and the contributions they make to people. It aims to develop decision support tools and methods to protect and sustainably use living natural resources.
2 CESCO (Sorbonne University, CNRS, National Museum of Natural History)
3 Group on Earth Observations Biodiversity Observation Network.
4 Biomass refers to the total amount of living organisms in a given environment at a given time.