Global biodiversity has been declining alarmingly despite a pledge by world leaders in 2002 to help curb the loss of earthly life forms, a new United Nations-supported study shows.

"Our analysis shows that Governments have failed to deliver on the commitments they made in 2002: biodiversity is still being lost as fast as ever, and we have made little headway in reducing the pressures on species, habitats and ecosystems," said Stuart Butchart of the UN Environment Programme's World Conservation Monitoring Centre (UNEP/WCMC) and BirdLife International, and the paper's lead author. The study is published in the latest edition of the journal Science.

In more than 30 indicators – measures of different aspects of biodiversity, including changes in species' populations and risk of extinction, habitat extent and community composition – the study found no evidence of a significant reduction in the rate of decline of biodiversity.

The pressures facing biodiversity continue to increase, the study reveals, and concludes that the 2010 target for reducing the loss of biodiversity has not been achieved. The findings represent the first assessment of how the targets made through the Convention on Biological Diversity (CBD) in 2002 have been missed.

"Since 1970, we have reduced animal populations by 30 per cent, the area of mangroves and sea grasses by 20 percent and the coverage of living corals by 40 per cent," said UNEP's Chief Scientist, Joseph Alcamo. "These losses are clearly unsustainable, since biodiversity makes a key contribution to human well-being and sustainable development, as recognized by the UN Millennium Development Goals (MDGs)," he said.

The results from the study feed into Global Biodiversity Outlook 3, the flagship publication of the CBD, to be released in Nairobi on 10 May, when Government representatives from around the world will meet to discuss the 2010 target and how to address the biodiversity crisis.

"Although nations have put in place some significant policies to slow biodiversity declines, these have been woefully inadequate, and the gap between the pressures on biodiversity and the responses is getting ever wider," said Dr. Butchart.

The study, however, recognized that there have been some important local or national successes in tackling biodiversity loss, including the designation of many protected areas – such as Juruena National Park in Brazil – and the recovery of particular species such as the European bison. Another success is the prevention of extinctions of some species, including the black stilt of New Zealand.

Despite these encouraging achievements, efforts to address the loss of biodiversity need to be substantially strengthened, and sustained investment in coherent global biodiversity monitoring and indicators is essential to track and improve the effectiveness of these responses, according to the study.

"While many responses have been in the right direction, the relevant policies have been inadequately targeted, implemented and funded," said Ahmed Djoghlaf, the CBD’s Executive Secretary. "Above all, biodiversity concerns must be integrated across all parts of government and business, and the economic value of biodiversity needs to be accounted for adequately in decision-making. Only then will we be able to address the problem."