More than two years ago, the Straight's Travis Lupick wrote a long feature about how the "Sixth Extinction" was playing out across B.C.

He pointed out that we've entered the Anthropocene Epoch, in which humans "are overtaking nature as the dominant force on Earth".

Lupick noted that 624 salmon species in the Pacific Northwest "are at high risk of extinction", according to one report, and another "142 populations had already disappeared since recording began in the mid–20th century".

"In 2013, there was a shocking collapse of sea-star populations," Lupick added. "Across the province, we’re losing songbirds, bats, and every species of bee we have. The causes aren’t always clear, often because there are multiple human factors at play."

A study published this week by the U.S.-based Proceedings of the National Academy of Sciences outlines the extent of the problem worldwide. And it's extremely disturbing.

Researchers at Stanford University and the National Autonomous University of Mexico examined population trends involving 27,600 species of birds, amphibians, mammals, and reptiles. That's half of the known land-based vertebrates.

"Dwindling population sizes and range shrinkages amount to a massive anthropogenic erosion of biodiversity and of the ecosystem services essential to civilization," they write in the abstract. "This 'biological annihilation' underlines the seriousness for humanity of Earth’s ongoing sixth mass extinction event."

It states that as much as 50 percent of the animals that once shared the planet with humans have disappeared.

The lion species, Panthera leo, for example, used to be all over most of Africa, southern Europe, the Middle East, and northwestern India. Now, these animals are scattered in sub-Saharan Africa and there's a remnant in the Gir forest of India, but the vast majority of these populations are gone, according to the study.

"Population extinctions today are orders of magnitude more frequent than species extinctions," the researchers state in their conclusion. "Population extinctions, however, are a prelude to species extinctions, so Earth’s sixth mass extinction episode has proceeded further than most assume.

"The massive loss of populations is already damaging the services ecosystems provide to civilization," they continue. "When considering this frightening assault on the foundations of human civilization, one must never forget that Earth’s capacity to support life, including human life, has been shaped by life itself."