World’s Total Animal Numbers Dropped ~50% Over Last Few Decades, Research Finds

The number of individual animals in the world — amongst birds, amphibians, mammals, and reptiles, etc. — has been reduced by as much as 50% over the last few decades, a new study published in the Proceedings of the National Academy of Sciences has found.

To put that another way, the last few decades, since 1990 or so, have seen the world’s non-human animal population essentially cut in half — there are only around half as many individual animals in the world now as there were in 1990.

“This is the case of a biological annihilation occurring globally, even if the species these populations belong to are still present somewhere on Earth,” commented co-author Rodolfo Dirzo, a professor of biology.

“The massive loss of populations and species reflects our lack of empathy to all the wild species that have been our companions since our origins,” commented study lead author, Gerardo Ceballos of the National Autonomous University of Mexico. “It is a prelude to the disappearance of many more species and the decline of natural systems that make civilization possible.”

That’s the blunt truth of it. While many modern people may consider themselves to be “above” the rest of the natural and animal world (humans are entirely “natural” in my opinion, not much different than any other social, generalist species to my eyes), the truth is that everything that people do, and the very existence of people in general, is only possible because of the rest of the natural world.

Trashing, looting, and diminishing the world to the degree that people have over the last few hundred years has been a profoundly stupid act.

Not too surprising though, as short-term binging does seem to often win out against long-term thinking when it comes to people. The exceptions to that tendency amongst humans is almost always the result of cultural and social systems that develop very slowly over time when human populations remain in a single environment — with earlier population crashes and cultural breakdowns seeming to lead directly to the establishment of new taboos and various socially and environmentally important forms of responsibility and accountability. I wonder what sorts of cultural taboos relating to “the environment” and other animals future human societies will have (presuming that people manage to stick around)?

The press release on the matter provides details about how the new study was conducted: “The researchers mapped the ranges of 27,600 species of birds, amphibians, mammals and reptiles — a sample representing nearly half of known terrestrial vertebrate species — and analyzed population losses in a sample of 177 well-studied mammal species between 1990 and 2015.

“Using range reduction as a proxy for population loss, the study finds more than 30% of vertebrate species are declining in population size and range. Of the 177 mammals for which the researchers had detailed data, all have lost 30% or more of their geographic ranges and more than 40% have lost more than 80% of their ranges. Tropical regions have had the greatest number of decreasing species while temperate regions have seen similar or higher proportions of decreasing species. Particularly hard hit have been the mammals of south and southeast Asia, where all the large-bodied species of mammals analyzed have lost more than 80% of their geographic ranges.

“The study’s maps suggest that as much as 50% of the number of animal individuals that once shared Earth have disappeared, as have billions of animal populations. This amounts to ‘a massive erosion of the greatest biological diversity in the history of Earth,’ the authors write.”

The impacts of this biological loss will greatly and increasingly affect everything from crop pollination, to pest control (insect and rodent population booms as the result of a loss of predators), to water purification via wetlands, to food/protein availability, etc.

So, in other words, even those that have lost the ability to maintain a sense of responsibility for the wider world, or the ability to sympathize with the parts of it that aren’t human for that matter, will be affected. Everyone from the tree huggers to the ranchers to the cubicle fauna will be affected, and to an every increasing degree, as the biological world continues to be diminished year by year. There will be no way to avoid this reality.

The researchers note that if this ongoing and very dangerous disaster is to be contained to any real degree that the basic drivers behind it will need to be addressed — meaning that human overpopulation and overconsumption will need to be addressed.

First, of course, these basic drivers of most of the world’s problems will need to be discussed politically, which is something that rarely ever happens, as the subjects are seemingly something of a taboo.

Image credit: Gerardo Ceballos

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