The Earth is experiencing its sixth great extinction, and humans are to blame for the event, according to a new study. Since the year 1900, around 470 species of vertebrates have been lost.
Stanford University researchers calculated the rate at which species are declining around the globe. Even using conservative estimates, the loss of plants and animals is greater now than at anytime since the end of the age of dinosaurs, the study concluded.
The extinction currently taking place threatens numerous species around the planet, including human beings. Researchers say the only hope for stemming the losses would involve actions to save natural habitats, but the opportunity to do so is quickly slipping away.
"If it is allowed to continue, life would take many millions of years to recover, and our species itself would likely disappear early on," said Gerardo Ceballos of the Universidad Autónoma de México, lead author of the study.
Many scientists have long held the belief that species are dying out around the globe at a faster rate than at any other time in the last 65 million years. A few scientists, however, held the notion that extinction rates used by those holding this theory were flawed, and that extinctions are not taking place as quickly as estimated. However, this new study shows that species are disappearing 100 times faster than the normal "background" rate.
Fossils of vertebrates were studied, and even if the background extinction rate is twice that estimated in most studies, the current loss of species still suggests the planet is currently experiencing its sixth great period of extinction.
"We emphasize that our calculations very likely underestimate the severity of the extinction crisis, because our aim was to place a realistic lower bound on humanity's impact on biodiversity," researchers wrote in the study.
Human beings appear to be playing a significant role in the current extinction, through climate change, the loss of habitat and pollution, the study concludes. Significant regions of natural habitats are taken over by human beings for use as fields, farms, and habitation. People also introduce invasive species into areas, where they use up resources that would normally be utilized by animals native to a given area.
According to the International Union for Conservation of Nature, 26 percent of all mammals and 41 percent of all species of amphibians are currently in danger of disappearing.
In addition to the direct loss of species, extinctions also affect the biosphere. For instance, if bees were to go extinct, many plant species could also be lost due to a lack of pollination. This significantly increases the risk posed to humans by species loss.
Analysis of the rate at which species are going extinct around the globe was published in the journal Science Advances.
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