Here, the fundamental questions relate to the impacts of climate change (melting glaciers, desertification, meteorological hazards, etc.), air, soil and water pollution, the massive destruction of ecosystems (deforestation, urbanization, artificialization of soils, etc.), overexploitation (forests) and the spread of species, some of which will prove to be formidable invasives (primrose willow, water hyacinth, Miconia, ragweed, etc.).), overexploitation (forests) and the spread of species, some of which will prove to be formidable invasives (primrose willow, water hyacinth, Miconia, ragweed, ragwort, etc.; rats, domestic animals on islands, etc.). Urbanization (in France, the equivalent of the surface area of a département every 7 years) and agriculture are two key factors. If some humans were able to live without agriculture (5 million at the beginning of the Neolithic?), there can be no humanity (7 billion today, 9 tomorrow) without agricultural production. Today, the challenge is clear: how can we produce more without indefinitely increasing farmland, without wasting water, without poisoning consumers, without toxic pesticides and insecticides, by reducing inputs, while preserving biodiversity? This is a major challenge for research, which also involves diversifying and maintaining agronomic varieties. The Earth cannot become a single, gigantic agrosystem, and we need to be able to feed 9 billion people more equitably tomorrow than we do today.
Tropical forests are disappearing at a rate of a quarter the size of France every year. 93% of Europe's "ancestral" forests have disappeared, but many are being replanted today, not always with the same species. The world's three great "forest basins" - Amazonia, Borneo, Papua and Congo - are threatened by demographic pressure and the advance of slash-and-burn agriculture. Madagascar has lost over 80% of the original forest that existed when humans arrived 20,000 years ago. We also need to do much more to advance our knowledge of soils. Plants and animals are moving under the influence of global warming, but everything is moving too fast and they don't have time to "hit the road". The disappearance of large predatory carnivores, pollinators, birds, etc., has catastrophic consequences for ecosystems and their capacity for resistance and resilience.
