One quarter of Earth’s species may be extinct by 2100
By using a scientific model created by one of Europe’s most advanced computers, a research team led by Flinders University in Australia has found that over a quarter of the world’s animals may go extinct by the end of the 21st century. According to the experts, ten percent of plants and animals will disappear by 2050 – a number rising up to 27 percent by 2100. Thus, the world could be facing a sixth mass extinction event much earlier and more dramatically than previously thought.
While earlier models of extinction trajectories have largely focused on different aspects, such as the direct impact of climate change or habitat loss on the fate of various species, this is the first study to interconnect species on a global scale in order to clarify how much additional loss may take place through “co-extinctions.”
“Think of a predatory species that loses its prey to climate change. The loss of the prey species is a ‘primary extinction’ because it succumbed directly to a disturbance. But with nothing to eat, its predator will also go extinct, a co-extinction. Or, imagine a parasite losing its host to deforestation, or a flowering plant losing its pollinators because it has become too warm,” explained study senior author Corey Bradshaw, a professor of Global Ecology at Flinders.
By using a cutting-edge computer, the scientists created “synthetic Earths” complete with virtual species and over 15,000 food webs. Then, climate and land use change scenarios were applied to the system to inform future projections.
“Essentially, we have populated a virtual world from the ground up and mapped the resulting fate of thousands of species across the globe to determine the likelihood of real-world tipping points,” said study lead author Giovanni Strona, an expert in Macroecology at the University of Helsinki.
“We can then assess adaptation to different climate scenarios and interlink with other factors to predict a pattern of coextinctions. By running many simulations over three main scenarios of climate until 2050 and 2100 — the so-called Shared Socioeconomic Pathways (SSP) from the Intergovernmental Panel on Climate Change (IPCC), we show that there will be up to 34 percent more co-extinctions overall by 2100 than are predicted from direct effects alone.”
The analysis revealed an even more frightening possible outcome: co-extinctions may raise the overall extinction rate of the most vulnerable species by up to 184 percent by the end of the century.
“This study is unique, because it accounts also for the secondary effect on biodiversity, estimating the effect of species going extinct in local food webs beyond direct effects. The results demonstrate that interlinkages within food webs worsen biodiversity loss, to a predicted rate of up to 184 percent for the most susceptible species over the next 75 years,” Bradshaw explained.
“Children born today who live into their 70s can expect to witness the disappearance of literally thousands of plant and animal species, from the tiny orchids and the smallest insects, to iconic animals such as the elephant and the koala … all in one human lifetime.”
The study is published in the journal Science Advances.
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By Andrei Ionescu, Earth.com Staff Writer
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