There have been five mass extinction events in Earth’s history, and numerous experts have warned that a The sixth mass extinction could already be underway as a result of human activities since the Age of Exploration. Some scientists have even suggested it almost 40% of the species (opens in new tab) currently living on our planet could be extinct as early as 2050.
But is this just a worst-case scenario? Is such a dramatic drop in Earthkind of likely to happen?
Related: Could climate change cause humans to become extinct?
A rising death toll
A sixth mass extinction is definitely plausible, said Nic Rawlence, director of the Otago Palaeogenetics Laboratory and associate professor of antiquities DNS at the Department of Zoology at the University of Otago in New Zealand.
“I think it’s quite likely,” Rawlence told Live Science in an email. “And unless species go extinct globally, it’s likely that those unable to adapt to our rapidly changing world will suffer range limitations, population bottlenecks, local extinctions, and functional extinctions.” The current extinction crisis may not yet have reached the heights of the Big Five, but it is certainly on the right track if nothing is done about it.”
According to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species (opens in new tab)around 41,000 – almost a third of all assessed species – are currently threatened with extinction.
Many known species and subspecies – including the Sumatran orangutan (Pongo abelii), Amur leopard (Panthera pardus orientalis), Sumatra elephant (Elephas maximus sumatranus), Black rhino (Diceros bicornis), Hawksbill Turtle (Eretmochelys imbricata)Sunda tiger (Panthera tigris sondaica) and Cross River gorilla (Gorilla gorilla diehli) – are classified as “Critically Endangered” according to the IUCN and the IUCN, meaning they face an extremely high risk of extinction in the wild World Wide Fund for Nature (opens in new tab) (WWF).
The IUCN describes them as Critically Endangered (opens in new tab) “a category that includes those species that have an extremely high risk of extinction due to a rapid population decline of 80 to over 90 percent in the last 10 years (or three generations), a current population size of fewer than 50 individuals, or other factors.”
Many of these species are so threatened that they may not make it to 2050. For example, only 70 Amur leopards remain in the wild during the Vaquita (Phocoena sinus), a species of porpoise thought to be the world’s rarest marine mammal, has dwindled to just 10 individuals, according to WWF (opens in new tab).
There are countless lesser-known species that are also endangered. A 2019 review published in the magazine Biological preservation (opens in new tab) found that more than 40% of insect species are now threatened with extinction, with the researchers noting that “more sustainable, ecologically-based practices” need to be adopted broadly to “slow or reverse current trends that allow for the recovery of declining.” Insect populations and protect the vital ecosystem services they provide.”
Numerous insect species are on the IUCN “Critically Endangered” list, including the white-tipped locust (Chorthippus acroleucus), Southern Alpine bush cricket (Anonconotus apenninigenus), Swanepoel’s blue butterfly (Lepidochrysops swanepoeli), Franklin’s bumblebee (Bombus Franklini) and the wingless groundhopper of the Seychelles (Procyttix fusiformis).
Related: What is the first species that humans brought to extinction?
The same dire prediction of a precipitous decline is in place for almost all life on Earth. According to a 2018 report (opens in new tab) by the Intergovernmental Panel on Climate Change (IPCC), more than 90% of the world coral reefs could be dead by 2050 even if global warming is kept to 2.7 degrees Fahrenheit (1.5 degrees Celsius). A recent IPCC (opens in new tab) But the report was even more damning, suggesting that by the early 2030s, a 1.5C global temperature rise could mean that “99% of the world’s reefs experience heatwaves that are too frequent to recover could”.
According to a 2022 report published in the journal Nature (opens in new tab)two in five amphibians (40.7%) are now critically endangered, according to a 2016 report published by the journal biology letters (opens in new tab) has found that by 2050, 35% of frogs in the Wet Tropics of Queensland, Australia “could be threatened with extinction”. In fact, the demise of amphibians may be even more pronounced. Scientists admit that there are many amphibians about which they have had difficulty gathering detailed information, and these species are classified as data deficient (DD). According to a report published in the magazine in 2022 communication biology, (opens in new tab) “85% of DD amphibians are likely to be critically endangered, as are more than half of DD species in many other taxonomic groups such as mammals and reptiles.”
It is therefore incredibly difficult to determine the exact number of species that are likely to become extinct by 2050, especially since the scale of the extinction has yet to be determined. Also, we don’t know how many species there are currently, making it nearly impossible to identify all endangered creatures.
That’s partly because “taxonomy — the science of naming biodiversity — is critically underfunded,” Rawlence said. “We can’t determine the number of species that are going extinct if we can’t name biodiversity (or name it fast enough before it goes extinct).”
While extinction occurs naturally – more than 99% of all species (opens in new tab) ever exist are already extinct – human activity can dramatically accelerate species extinction – an idea close to New Zealander Rawlence’s.
“Island ecosystems are the perfect example to illustrate this,” he said. “They are isolated and often contain high levels of endemicity (i.e. unique wildlife).” New Zealand has grown from about 230 bird species at the time of human arrival to about 150 species now — a loss of about 80 bird species, Rawlence said.
Related: How long do most species survive before becoming extinct?
Given the time, many species can adapt to changes in climate and changes in their natural environment. A 2021 research paper in the journal Trends in Ecology & Evolution (opens in new tab) found that some animals “change their morphologies” to better deal with them climate change, with some birds appearing to be the most adaptable. According to the research, several species of Australian parrots have evolved over the past 150 years to larger beak sizes, an adaptation that allows them to better regulate their internal temperature.
But as human activities accelerate climate change and habitat depletion, some of the most vulnerable species will likely bear the brunt and become unable to adapt.
what can be done
With so many species currently on the brink of extinction, is there anything we can do to prevent the worst-case scenario?
For one, “the trade-off between short-term political gain and long-term funding for conservation initiatives needs to be resolved,” Rawlence said. “Many of our endangered species survive only through intensive conservation management. When state and public will and resources erode, it will be a very different situation.”
Of course, there are a multitude of organizations, researchers and projects that have set themselves the task of slowing down or even stopping man-made climate change. climate works (opens in new tab), a company based in Switzerland, is a pioneer in the field of CO2 air capture technology and aims to build a series of plants capable of removing CO2 from the air forever. The first plant opened in Iceland in 2021.
Elsewhere, Project Drawdown (opens in new tab)founded in 2014, is a non-profit organization that aims to bring together experts around the world so they can propose and test concepts to stop them greenhouse gases in the atmosphere from rising, and will eventually see them fall while Bill Gates support Stratospheric Controlled Disturbance Experiment (opens in new tab) is currently studying the possibility of spraying non-toxic calcium carbonate (CaCO3) dust into the atmosphere to reflect sunlight and thereby offset or significantly reduce the effects of global warming.
In the meantime, we must look to the past to inform the future of the planet, Rawlence said.
“To save the remaining biodiversity, we need to know how it has responded to past and present climate changes and human impacts so that we can predict how it might respond in the future, backed by evidence-based conservation management strategies,” he said.
In short, more research and hard work is needed – before it’s too late.
Originally published on Live Science.
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