Earth could lose more than a tenth of its plant and animal species by the end of the century on current trends, according to new research that comes as nearly 3,000 scientists call on governments to act to stop the destruction of nature in the final days of negotiations. at COP15.
The climate crisis will lead to an accelerating cascade of extinctions in coming decades, as predators lose prey, parasites lose hosts and rising temperatures fracture Earth’s web of life, according to researchers. researchers, who warn of the risk of co-extinctions in an article published Friday in Science Advances.
From leaf frogs to basking sharks, the risk of extinction of plants and animals is commonly monitored on the IUCN Red List, where scientists have published their analysis of threats to more than 150,388 species, finding that more than 42,000 could disappear, often because of man. behaviour.
However, the new research used a supercomputer to model a synthetic Earth complete with virtual species to understand the effect global warming and land use change could have on the web of life. Researchers say 6% of plants and animals will disappear by 2050 in a mid-road emissions scenario, which the world appears to be heading towards, rising to 13% by the end of the century. In the worst case of global warming, they estimate that 27% of plants and animals could disappear by 2100.
“We populated a virtual world from scratch and mapped the resulting fate of thousands of species across the globe to determine the likelihood of real-world tipping points,” said co-author Dr Giovanni Strona and scientist at the University. from Helsinki.
“This study is unique because it also takes into account the secondary effect on biodiversity, estimating the effect of species extinction in local food webs beyond the direct effects. The results demonstrate that the interconnections within food webs exacerbate biodiversity loss,” said study co-author Professor Corey Bradshaw of Flinders University in Australia.
“Think of a predator species that loses its prey due to climate change. The loss of the prey species is ‘primary extinction’ because it succumbed directly to a disturbance. But without anything to eat, its predator will go extinct as well. (a co-extinction. Or imagine a parasite losing its host to deforestation, or a flowering plant losing its pollinators because it’s too hot. Each species depends on the others in one way or another. “, did he declare.
Using hundreds of virtual Earths populated by more than 33,000 species, scientists examined how relationships between virtual plants and animals change due to different drivers of biodiversity loss. Virtual species were able to recolonize new regions of the planet and adapt to changing conditions in the model, say the researchers, who found climate change to be the main driver of extinctions.
The research comes as discussions at the biggest biodiversity conference in a decade are reaching a boiling point in Montreal. More than 100 environment ministers from around the world are discussing this decade’s goals to protect the Earth’s biodiversity. With the city’s first major snowstorm of the winter, late-night talks are expected this weekend as ministers seek to resolve divisions between the world’s north and south over funding for new development projects. conservation goals to protect 30% of the Earth and restore an area the size of China.
In an open letter, more than 2,700 scientists called on governments to tackle the overconsumption of Earth’s resources in the final text and start reversing biodiversity loss by 2030.
“Parties at COP15 must commit to halting and beginning to reverse biodiversity loss by 2030, to put us on a path to recovery where ecosystems can provide the functions people need. There is a moral obligation to do so. Moreover, it makes scientific sense and is achievable if we act now and decisively. We owe it to ourselves and to future generations – we can’t wait any longer,” reads the letter, signed by leading scholars.
It says action on biodiversity loss in the Cop15 agreement, known as the global biodiversity framework, must involve agricultural transformation, and warns that a delay in meaningful action on nature destruction will exacerbate human poverty and inequality.
“We will not succeed without putting equal effort into goals and targets related to fundamental drivers of ecosystem destruction and biodiversity loss, including making our supply chains resilient and sustainable,” the letter reads.
“This requires paying attention to the disproportionately harmful consumption of rich countries, as well as the rights and priorities of disadvantaged groups. Critically, this means that wealthy nations and actors must urgently and quickly reduce the impacts of their consumption, rather than imposing all the costs of nature restoration on less wealthy nations where biodiversity remains prevalent” , indicates the letter.
Negotiations are due to end on Monday, December 19, although they risk being overrun.
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