NaturePL

GREEN-MINDED folk of many shades came to Spain this month, to talk about the need to save from human recklessness as much as possible of nature's bounty of genes, habitats and species. They brought bad tidings. Common birds are in decline across the world. Almost one in four species of mammals is in danger of extinction. If current trends continue until 2050, fisheries will be exhausted. As it is, deforestation costs the world more each year than the current financial crisis has cost in total, one economist argued.

In theory, virtually all the world's governments are committed to limiting the damage. In 1992, at the Earth summit in Rio de Janeiro, they signed a treaty called the Convention on Biological Diversity (CBD). In 2002, under its auspices, they vowed to bring about “a significant reduction” in the rate of loss of biodiversity by 2010. The pledge became one of the Millennium Development Goals, the United Nations' eight fondest ambitions for the world.

Yet this target now looks unattainable, said most participants at the World Conservation Congress, which concluded in Barcelona on October 14th. The meeting was awash with gloomy forecasts. The International Union for the Conservation of Nature (IUCN), the network of conservation groups that organised the congress, released the latest version of its “red list” of threatened species. It describes the health of all species whose populations have been assessed—almost 45,000 this time round. At first glance, the proportion of species at risk seemed to have fallen slightly. But that, the compilers note, simply reflects the expansion of its coverage beyond the creatures seen as most in danger. Of 223 species whose status has changed since last year, 82% were closer to extinction.

The IUCN also released a “comprehensive assessment” of the status of all known species of mammals. It found that 22% were threatened or extinct, and the well-being of a further 15% was unknown. For amphibians, the outlook is grimmer: a full 31% of them are at risk, and the status of a further 25% is uncertain. Sampling of species in other categories suggests similarly dire outlooks, with some 24% of reptiles and 32% of crabs thought to be threatened. For the most part, these findings do not reflect the latest data on global warming. But another IUCN study released at the congress found that 35% of the world's birds, 52% of its amphibians and 71% of its warm-water corals were “particularly susceptible” to the threats from warming.

Last year, the Intergovernmental Panel on Climate Change, which is studying global warming for the UN, said 20-30% of species could die out if global average temperatures rise by more than 2°C or so. And even today's rate of extinctions, one Barcelona delegate noted, is 1,000 times faster than the norm before man made a mess.

What does the loss of other species cost humans? Many congress-goers talked about valuing “ecosystem services”: natural processes that benefit people, such as the pollination of crops, the purification of water in wetlands and the sequestration of carbon in soil and forests. A study released this year said the world was losing €50 billion ($68 billion) in ecosystem services each year because of damage to nature.

Biodiversity underpins ecosystem services. Bees can't pollinate, nor can trees store carbon, if they have all died. And it seems to matter that ecosystems contain more than a handful of species. Diverse systems are better at capturing carbon, storing water and preserving fisheries. Just how diverse an ecosystem has to be in order to supply the goods and services needed by man is a matter of debate—a debate made harder by the fact that many species may have uses that man has not yet found. And regardless of its uses for humans, many see a moral imperative to save biodiversity. Ecuador's new constitution duly confers on ecosystems “the inalienable right to exist, flourish and evolve”.

In a report for the British government, Johan Eliasch, a businessman and environmentalist, suggests a virtuous circle: climate change could be slowed, biodiversity saved and poverty alleviated if forests were included in carbon markets. Deforestation is responsible for so many emissions that allowing countries to claim carbon credits for reducing the pace at which they cut down their forests could cut the cost of halving global carbon emissions from 1990 levels by 2030 by 50%. And, in the process, deforestation rates would be reduced by 75% by 2030. But this would cost the rich world money: $4 billion over the next five years, and a further $11-19 billion a year by 2020.

In the short term, there is little sign of governments becoming better stewards of nature. Only 30 or so of the 191 countries that are party to the CBD have made plans to protect biodiversity, as the treaty demands. Another study released at the congress found that the world's biggest economies were spending only a fraction of the money needed to police protected areas; they were also falling short on legal and administrative measures needed to stop the spread of invasive species and eradicate the trade in endangered species. Money, of course, is likely to get tighter as the world economy slows and governments rescue struggling banks.

Many at the congress said that nature, too, needed a bail-out. As Andrew Mitchell of Global Canopy Programme, a forest-conservation group, puts it: “Rainforests work as a giant natural utility company. If we don't start paying for it, we will get cut off. Instead of simply preventing the next global credit crunch, it is time to start thinking about averting the rainforest crunch as well.” Julia Marton-Lefèvre, the head of the IUCN, agrees. “Business as usual is simply not an option,” she says. But that is the option many governments seem to be choosing.