One in five vertebrate species could be set for extinction, says an international group of scientists.
Their analysis, published in Science, concludes that on average, 52 species of mammals, birds and amphibians are moving one category closer to extinction each year.
The authors analyzed the International Union for the Conservation of Nature (IUCN) Red List, which covers oiver 25,000 vertebrate species.
"There is no question that business-as-usual development pathways will lead to catastrophic biodiversity loss," comments Dr Paul Leadley, of the University Paris-Sud. "Even optimistic scenarios for this century consistently predict extinctions and shrinking populations of many species."
He adds that the target of stopping biodiversity loss by 2020 "sounds good, but sadly isn't realistic."
Nevertheless, human efforts have made a difference, says the team, which reckons that overall declines would have been approximately 18 percent worse without any conservation actions.
But for the future, they say, the window of opportunity is closing rapidly, as differences in policy action taken now could either lead to an increase in global forest cover by 2030 of about 15 percent in the best case or losses of more than 10 percent in the worst.
The authors call for the creation of an Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), along the lines of the Intergovernmental Panel on Climate Change (IPCC).
"The issues are so urgent and the stakes for humanity so important, scientists need to coalesce through the IPBES to inform policy-makers with a unified, authoritative voice," says Dr Henrique Miguel Pereira of the Universidade de Lisboa.
Such a body could also perhaps make sense of the vastly differing projections of biodiversity that currently exist - while some foresee extinction rates staying much the same as at present, at less than one percent per century, others are predicting this will rise to more than 50 percent.