One fifth of the world's vertebrates are threatened with extinction. That's the word from the 10th Conference of the Parties to the Convention on Biological Diversity this week in Nagoya, Japan, where a team of 174 scientists presented an assessment of the world's at-risk vertebrate species.

According to the study, published in the October 28 issue of Science, the number of threatened species has grown dramatically in the past four decades, exceeding the normal "background rate" of extinction by a factor of two or three. The IUCN Red List of Threatened Species currently lists 25,780 vertebrates as threatened, and an average of 52 species become more threatened (based on the IUCN's categories of risk) every year.

"The 'backbone' of biodiversity is being eroded," said Harvard University entomologist Edward O. Wilson in a prepared statement. "One small step up the Red List is one giant leap forward towards extinction. This is just a small window on the global losses currently taking place."

There is small amount of good news accompanying this study: The wide range of conservation efforts around the world has actually slowed this rate of extinction.

But current conservation efforts are far from adequate. According to a second study, also presented at the conference and published in the same issue of Science, the world would need to spend 10 times as much as it currently does on conservation in order to halt the pending extinction of many species. "There is no question that business-as-usual development pathways will lead to catastrophic biodiversity loss," said one of the second study's lead authors, Paul Leadley of the University of Paris–Sud, in a prepared statement. "Even optimistic scenarios for this century consistently predict extinctions and shrinking populations of many species."

The authors point out that all changes in species population size and distribution matter, as they reflect the health and well-being of the dominant species on the planet: humans. If species are dying out, it is an indication of the long-term health of our own species, and we need to be aware of the impact we are having on our own ecosystem.

Photo: Endangered bonobo (Pan paniscus) via Wikipedia