UN sounds biodiversity mayday

Human activity is causing the biggest loss in biodiversity since the extinction of the dinosaurs, a UN report says.

Released to mark the start of the UN environment programme meeting in Curitiba, Brazil, the Biodiversity Outlook 2 calls for rapid and decisive intervention to avert further species loss.

A flock of worrying statistics front up the report.

As much as 80 per cent of Caribbean hard coral cover has vanished in the last 30 years. Large North Atlantic fish have endured a two-thirds drop in numbers. Up to around half of higher birds are threatened with extinction.

Disturbingly, every year since the turn of the century 6m hectares of natural forest have been destroyed. The bulk – around 4m hectares – disappear annually from Africa, which can scarcely afford to lose what natural resources it does have.

Even where habitats are relatively intact in terms of sheer area, they are becoming fragmented. This puts huge pressure on their ability to support biodiversity.

Productive ecosystems are the foundation of human wellbeing, the authors say. A recent survey showed that 15 out of 24 markers of ecosystem health - from fishery stocks though to water supplies and atmospheric cleanliness - were in decline. In fact, overall demand for ecological resources outstrips supply by 20 per cent.

Alien species introductions brought about by human activity are bad news for biodiversity too. Since the opening of the Suez canal, some 300 species have invaded the Mediterranean from the Red Sea, out-competing natives that occupy a similar niche in the ecosystem.

The financial hit from introduced pests is estimated at over $100bn.

The overall picture frames humanity's effect on global biodiversity in a geological context; there have only been five mass extinction events in the history of Earth that compare. We're now in the same destructive league as asteroid strikes, enormous flood basalts and ice ages.

The new report paints an even more grim picture than the first Biodiversity Outlook, released in 2001. In response to that assessment the UN set a target in Johannesburg in 2002 to achieve a “significant reduction in the rate of biodiversity loss by 2010”.

That's now looking increasingly unlikely.

In effect then, the current Curitiba meeting is a last-gasp effort to rescue that target, “by no means impossible”, according to the new report's authors, though it requires "unprecedented action".

The authors urge better habitat protection, pollution curbs, and resource management.

Labour has sent DEFRA minister Jim Knight to Curitiba. Though with relatively little biodiversity of its own to preserve, Britain's role must be to support efforts in the tropics, which play host to unimaginable numbers of species.

Survey the gloom for yourself here (8Mb/pdf). ®