“Human population size is able to predict past extinctions with 96% accuracy,” the experts argue.
Many of the 5,700 mammalian species around the planet are facing grave existential threats and they are likely to go extinct in the near future.
So say a team of scientists who have used computer simulation and Bayesian modelling to track the fate of mammals since the beginning of the Late Pleistocene more than 120,000 years ago. What they have found is that humans have had a far greater impact on the extinction of mammals than changing climates, which have had “a negligible impact.”
“Mammoths, for example, survived several ice ages before the last one and there is no climatic reason why they should not be alive in Siberia today,” notes Daniele Silvestro, a computational biologist who was an author of a new study.
That may sound counterintuitive in the face of the various threats from climate change, yet “human population size is able to predict past extinctions with 96% accuracy,” the experts argue. “Based on current trends, we predict for the near future a rate escalation of unprecedented magnitude,” they write in .
Over the past 126,000 years no fewer than 351 species of mammal have gone extinct on Earth with around 80 species having done so over the past 500 years alone from so-called Tasmanian tigers in Australia to actual indigenous tigers on Bali.
And as human populations continue to grow across much of the planet with increasing ecological impacts, the rate of mammalian extinction is accelerating to a rate that is 1,700 times higher than at the beginning of the Late Pleistocene. Generally, the more people live concentrated in a certain area, the higher the rate of extinction among larger slow-bleeding mammals there, according to the scientists who employed computer models to reach their conclusion.
We have long known that continued habitat loss and poaching or hunting can greatly imperil populations of mammals, especially in places with large numbers of people. However, even relatively few people can wreak havoc with endangered animals.
Based on current trends the researchers predict that as many as 558 species of mammal will have gone extinct in the wild by the end of this century. “By the year 2100, we predict all areas of the world to have entered a second wave of extinctions,” they warn, adding that the rate of extinction then will be 30,000 times the natural level.
In some areas of the planet mass extinctions of larger mammals are already well under way as a result of human activities. “We find that Australia and the Caribbean in particular have already today entered the second extinction wave based on the extinctions that have occurred during the past decades,” the scientists write.
This does sound pretty beak, but not all is lost. At least not yet. “We can save hundreds of species from extinction with more targeted and efficient conservation strategies,” stresses Tobias Andermann, a biologist at the University of Gothenburg who was the first author of the study.
“But in order to achieve this, we need to increase our collective awareness about the looming escalation of the biodiversity crisis and take action to combat this global emergency,” he adds. “Time is pressing.”