Saving all the world’s endangered species could cost US$4 billion a year, according to the first global estimate of the likely cost of comprehensive conservation1. If that number doesn’t seem staggering enough, the scientists behind the work think that effectively conserving all the significant areas these species live in could come to over $76 billion a year.

Stuart Butchart, a conservation scientist at BirdLife International in Cambridge, UK, and lead author of the latest study, admits the numbers seem very large. But he points out that “in terms of government budgets they’re quite trivial” and that governments have already committed to taking this action, they just had no idea before how much it would cost.

In their paper in Science, his team also points out that the annual costs of proper conservation are but a fraction of the value of ‘ecosystems services’ from nature, such as pollination of crops and carbon sinks. “These sums are not bills, they’re investments in natural capital,” says Butchart. “They’re dwarfed by the benefits we get back from nature.”

Under the Convention on Biological Diversity (CBD) governments have committed to meet a number of conservation targets by 2020, including improving the conservation status of threatened species. To come up with numbers for how much this might cost the team started by looking at the world’s birds, asking experts on 211 threatened species to estimate the likely cost of moving a given animal down one category on the IUCN’s ‘red list’, which assigns a ranking from ‘least concern’ to ‘extinct’.

Costing the Earth

From this they concluded that improving the status of all the world’s threatened birds would run to between $875 million and $1.23 billion, per year, for the next decade. Adding in other animals raises the number to $3.41 to $4.76 bn per year.

Another target under the CBD – albeit one there whose attainability is in doubt – is to protect 17% of the Earth’s land surface. Estimates for this are harder to make, but Butchart’s team puts the number at $76.1 bn a year.

Exactly how much is currently being spent to meet the convention’s targets is also unclear, but Butchart says spending will need to increase by “an order of magnitude”. And while there is a large amount of uncertainty in these numbers, now that they are public governments can start to make plans for how they might start trying to meet the targets they have already agreed to.

Henrique Pereira, who works on international conservation issues at the University of Lisbon in Portugal, says that although there are uncertainties inherent in extrapolating from birds to all species, the work is an “extremely smart paper”.

“For the first time we have an estimate of how much these targets will costs,” he says. “For any negotiations that occur over the next few years [on CBD targets] these numbers can be used as a reference.”

But Pereira also cautions that the figure is for just two of the 20 targets agreed by the CBD. “If you look at the range of targets for 2020, the total bill will be higher.”

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