Science.- Cascading extinctions will end this century with 25% of species – Publimetro Peru

Madrid, 19 years old (Europe Press)

This is what a new tool developed by European and Australian scientists allows for unprecedented modeling of correlative loss of species, the results of which have been published in the journal Science Advances.

Using one of the most powerful supercomputers in Europe, Dr. Giovanni Strona, a scientist at the European Commission and also at the University of Helsinki, and Professor Cory Bradshaw, from Flinders University, used the tool to create an artificial Earth with virtual species. More than 15,000 food webs to predict the interconnected fate of species likely to disappear under the weight of climate change and land use.

The tool makes a grim prediction for the future of global diversity, confirming beyond any doubt that the world is in the midst of a sixth mass extinction event.

The two scientists say that previous approaches to assessing extinction trajectories over the next century have been hampered by their failure to incorporate co-extinction, that is, species that go extinct because other species on which they depend are subject to climate change and/or landscape changes.

“Think of a predator species losing prey to climate change. The loss of a prey species is “fundamental extinction” because it succumbed directly to the disturbance. But with nothing left to eat, its predator will also go extinct (“co-extinction”).”). Or imagine a parasite losing its host to deforestation, or a flowering plant losing pollinators because it’s too hot. All species depend in some way on other species, Professor Bradshaw said in a statement.

Until now, researchers have been unable to correlate species on a global scale to estimate how many additional losses would result from co-shrinkage. Although there are many excellent analyzes examining different aspects of extinctions, such as the direct effects of climate change and habitat loss on the fate of species, these aspects are not necessarily correlated realistically to be able to predict the magnitude of the extinction cascade. extinction.

Strona and Bradshaw’s solution to this problem was to build a huge virtual Earth from interconnected networks of species linked to who eats whom, and then apply climate and land use changes to the system to inform future projections.

Hypothetical species can also repopulate new areas with climate change, adapt to some extent to changing conditions, and die out directly as a result of global change, or fall victim to extinction chains.

“Essentially, we populated a virtual world from scratch and mapped the resulting fates of thousands of species across the planet to determine the likelihood of real-world tipping points,” explains Dr. Strona.

“We can then assess adaptation to different climate scenarios and correlate them with other factors to predict a pattern of co-expansions.”

“By running several simulations in three major climate scenarios up to 2050 and 2100 — the so-called Joint Socioeconomic Pathways (SSP) of the Intergovernmental Panel on Climate Change (IPCC) — we show that in 2100 there will be up to 34% expansions. common ones in general. than those predicted only by direct effects”, Strona emphasizes.

Even more terrifying, says Prof Bradshaw, co-extinctions will push the overall extinction rate for the most vulnerable species to 184% by the end of the century.

“This study is unique, in that it also takes into account the secondary impact on biodiversity, estimating the impact of species extinction on local food webs beyond direct effects. The results show that interrelationships within food webs worsen biodiversity loss, up to the expected rate. to 184% for the most susceptible species in the next 75 years.

“Compared to traditional extinction prediction approaches, our model provides detailed insights into variability in patterns of species diversity that respond to the interaction between climate, land use, and ecological interactions.” Children born today who turn 70 can expect to witness the demise of literally thousands of plant and animal species, from the smallest orchids and smallest insects to iconic animals such as the elephant and koala…all in one human life,” says Professor Bradshaw.

“The model produces realistically structured networks and a plausible regional distribution of species body masses, which reflects real-world evidence and validates our approach. We evaluated simulated climate and land use impacts on a monthly basis from 2010 to the year 2100 for species extinction, leaving no doubt that climate change In all scenarios it is directly responsible for most of the primary extinctions and co-extinctions,” Struna says.

Professor Bradshaw explains that despite the general appreciation that climate change is now a major driver of extinction globally, the new analysis clearly shows that we have so far underestimated its true impact on the diversity of life on Earth. Without major changes in human society, we risk losing much of what sustains life on our planet.

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