Session 5 is the last course to deal with the subject of biodiversity & society, with subsequent courses focusing on the company's approach to biodiversity.
The aim of this session is to review the main concepts studied during the first 4 sessions through a focus on the oceans: the three levels of biodiversity diversity, ecosystem services, the interdependence of biodiversity and economy, the impact of human activities, of climate change and the current efforts of conservation.
The ocean covers 70% of the planet, and in the face of this “deep blue” we often forget the wide variety of ecosystems and species (over 2 million species) it comprises: from pitch black abyssal trenches, to polar waters, kelp forests, underwater canyons, coral reefs or shallow coastal zones.
The ocean provides numerous ecosystem services. Some are very obvious, such as fishing (the basis for the diet of 3 billion people), or the role played by marine ecosystems in culture and tourism. Others are less well known, such as the role of ocean currents as climate regulators, ocean carbon sinks, phytoplankton as oxygen emitters, and coastal ecosystems like mangroves as protectors against erosion and natural disasters.
In most marine ecosystems, marine populations have collapsed (-50% since 1970 in the thousands of populations monitored by WWF) and fish stocks are being overexploited.
The cause: unbridled industrial fishing, with its habitat-destroying, non-selective methods, which have weakened fish populations and whose catches have been declining since the late 90s, despite subsidies, technological innovations and ever-deeper nets (+500m deep).
To halt the erosion of biodiversity, the signatory countries of COP15 (2022) committed to protecting 30% of terrestrial and marine ecosystems by 2030. Today, only 8% of coastal waters and oceans are protected, mainly within EEZs (exclusive economic zones). High seas (international waters) account for 60% of the Earth's surface, and are currently poorly regulated or protected. This situation is set to change thanks to the Treaty for the Protection of the Marine Environment Across Borders (2023).
Rising demand for fish and the homogenization of diets (international fashion for salmon, shrimp, etc.) are putting too much pressure on fish stocks and encouraging the growth of aquaculture, which is often intensive and therefore a source of heavy local pollution. Revising fishing methods, returning to the consumption of species according to the catches made, protecting marine areas and sensitive habitats to regain abundance are the solutions advocated by the scientific community to reconcile conservation and the development of the local economy.
The second part of the course (1h30) is dedicated to discussion in small groups on man's place in the living world, the philosophical notion of nature and the place of biodiversity in our societies.
Discussions are guided by a few questions and led in two stages: firstly, by letting the students base themselves on their preconceptions, and secondly by sharing their knowledge (from ethology, biology, law, theology...). The aim is to get them to take a step back and realize that the vision of man as “above nature” is more a cultural belief than a scientifically proven reality.
Prior to the exchanges, a framework of trust is established with the students to ensure the smooth running of this session (no interruptions, respect for contradictory opinions, confidentiality of personal sharing, no irony or mockery...).