UN: Crises are interconnected

Trouble never comes alone, not even in climate issues. The ways in which people consume and feed themselves are causing "interconnected" crises that affect biodiversity, climate and health, threatening the survival of essential ecosystems such as coral reefs, experts from around the world warned Tuesday in a landmark report. "Unsustainable agricultural practices", through the use of chemical fertilizers and pesticides, have multiple negative effects: loss of biodiversity, unsustainable use of water, pollution and greenhouse gas emissions.

• Links between biodiversity, water, food and health

The conclusions, adopted by nearly 150 countries meeting in Namibia, are the result of three years of work by a team of 165 experts from around the world gathered in the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES). These leading scientists - considered the biodiversity equivalent of the IPCC's UN-mandated climate experts - list in the report entitled ""Nexus'' the links between biodiversity, water, food and health. According to them, the crises affecting our planet are ""all interconnected''. ""There is a real danger of solving one crisis and worsening others,'' explained Paula Harrison, one of the study's lead co-authors. Coral reefs dramatically illustrate this warning: they are not threatened solely by warming oceans. "Even if we solve the climate problem, coral reefs will continue to be affected by pollution, overfishing and other threats," said American professor and co-lead author of the study, Pamela McElwee. The result: corals are "the most threatened ecosystem" on Earth and "could disappear on a global scale in the next 10 to 15 years," concluded IPBES. Page after page, scientists warn of the dire consequences of trying to solve one problem without thinking about others, such as taking a "single-minded" approach to climate change and ignoring the effects on nature. Some climate solutions can "come at a cost to biodiversity," said professor Pamela McElwee. For example, planting trees that absorb more CO2 can harm the local ecosystem if the species are chosen incorrectly, or it can lead to a reduction in the area available for growing food. Some climate-friendly wind farms can increase bird and bat mortality.

• One-size-fits-all solutions

At the other extreme, there are solutions that tick all the right boxes. "Reducing overconsumption of meat" is cited as an example among the 71 "answers" proposed and can have multiple beneficial effects. "Among good examples, we can cite marine protected areas, which have involved communities in management and decision-making," Pamela McElwee pointed out. "These areas have allowed for increased biodiversity, increased fish abundance to feed the population, improved local community incomes and, often, increased tourism revenues," she added. Experts cite funding from the city of Paris to encourage farmers to adopt more sustainable practices, with health and environmental benefits and reduced water treatment bills. In California, a ban on burning stubble was primarily aimed at improving the respiratory health of residents. But resorting to flooding these fields in the winter has allowed salmon habitat to be restored. But beyond these consensus recommendations, the experts - whose conclusions are politically approved by the country's representatives - have had difficulty agreeing on other issues.

• Changes on thorny issues

Several delegates demanded last-minute changes on thorny issues such as agricultural exports, fossil fuels, single-use plastics and consumption patterns.

They disputed the inclusion of the phrase "climate change" in the title of the report, according to the Earth Negotiations Bulletin. In the end, the phrase does not appear in the title.

Such frictions between countries have disrupted other UN environmental negotiations this fall (on biodiversity, plastics and desertification), which have failed in some cases. Half of the world's economy depends on nature, but human societies spend more on destroying nature than on protecting it, the report says. The social and environmental costs caused by fossil fuels, agriculture and fishing reach almost $25 trillion annually, equivalent to a quarter of global GDP, the authors estimate.