Nearly Half of Earth’s Animal Species Are in Decline, Study Finds

In a study on more than 71,000 animal species around the world, researchers discovered that about 48% are declining. The research, led by Queen’s University Belfast, is one of the most comprehensive and alarming studies on biodiversity loss.

The researchers analyzed population data on mammals, reptiles, amphibians, birds, fish and insects.

The study differs from the IUCN’s Red List, which found 28% of over 150,000 species studied to be threatened with extinction. But the authors explained that the data uncovered with their methods shows that the issue is much worse. According to the study, 33% of species designated non-threatened by IUCN were in decline.

“Almost half of animals on Earth for which assessments are available are currently declining,” Catherine Finn, leading author of the study, said in a statement. “To make matters worse, many of the animal species that are thought to be non-threatened from extinction, are in fact progressively declining.”

Another 49% of the species were found to have stable populations, while only 3% were experiencing increases. These findings were published in the journal Biological Reviews.

While biodiversity loss is a known issue globally, even prompting concerns that Earth is currently experiencing a sixth mass extinction, the study authors noted that this data shows the problem is even worse than previously thought. Furthermore, unlike previous mass extinction events, “this mass extinction is the first directly induced by a single species – humans,” the authors wrote.

According to the World Wildlife Fund, human activities including land, water and energy use are driving declines in biodiversity. Agriculture alone is responsible for 90% of deforestation and 70% of freshwater consumption globally. Greenhouse gas emissions and climate change further threaten species and ecosystems.

Although extinction is a natural process, extinction rates are now 1,000 to 10,000 times faster than the rates of natural extinction, WWF reported.

“This new study method and global-scale analysis provides a clearer picture about the true extent of global erosion of biodiversity that the traditional approach cannot offer,” said Daniel Pincheira-Donoso, principal investigator of the project and senior lecturer on evolutionary biology at Queen’s University Belfast. “Our work is a drastic alert about the current magnitude of this crisis that has already devastating impacts on the stability of nature as a whole, and on human health and wellbeing.”