Bonn, Germany - An economic value needs to be placed on biodiversity loss with the aim of creating appropriate markets and improving efficiency, experts Thursday told a UN biodiversity conference being held in Bonn.

Development economist Pavan Sukhdev put the annual loss to the world economy at up to 3.1 trillion euros (4.8 billion dollars) in lost capital over the first half of this century.

Taking just forest biomes, for which considerable data had been collected, Sukhdev said that by 2050, if current policies were continued, the global loss in gross domestic product terms would amount to 6 per cent.

'This is just in direct and indirect use values - food, water collection, flood prevention and so on... It does not include non-use values, such as ethical values,' said the economist who has previously conducted a similar study for the Indian government.

Sukhdev presented an interim report entitled The Economics of Ecosystems and Biodiversity to the conference, which is being attended by 6,000 delegates from 200 countries.

The report, commissioned by EU Environment Commissioner Stavros Dimas and German Environment Minister Sigmar Gabriel, said new ways of 'valuing nature' needed to be found to provide an economic basis for the protection of ecosystems.

Gabriel noted that little progress had been made on the UN's Convention on Biological Diversity (CBD) and attributed this in part to the lack of an economic valuation of what was being lost.

'We need to place a value on biodiversity to ensure efficient use,' he said.

This should not be understood as merely looking for new ways to make profits, the German environment minister said. But appealing purely to ethical standards had only limited effect.

Dimas referred to a 'strong moral imperative' for humankind to protect and conserve the world and said evidence was increasingly emerging that humanity was suffering measurable effects from its poor husbandry in the past.

Sukhdev's report found a close link between poverty and the loss of ecosystems and warned that the 'business as usual' approach would mean the loss of vast natural areas and of the species in them.

'We find poverty and the loss of ecosystems and biodiversity to be inextricably intertwined,' it said.

The main immediate beneficiaries of ecosystems and biodiversity were the poor, with the livelihoods most affected being subsistence farming, animal husbandry, fishing and informal forestry, it said.

The report called for those who contribute to maintaining sensitive ecosystems to be allowed to share in the benefits. Economic tools needed to be developed to measure the costs and benefits of conservation.

It was critical of current agricultural policy in the industrialized world. 'We need to rethink today's subsidies to reflect tomorrow's priorities,' it said.

Continuing along the current path would mean that by 2050, 11 per cent of the natural areas left in 2000 would be lost to agriculture or as a result of climate change.

In addition, 40 per cent of land under low impact agriculture in 2000 would be converted to intensive agriculture with resultant loss of biodiversity.

And 60 per cent of coral reefs would succumb to fishing, pollution, disease and the unintended introduction of invasive alien species, apart from the bleaching effects resulting from higher temperatures caused by climate change.

Since 1900, the world had lost 50 per cent of its wetlands, with the damage in the first half of the 20th century being done in northern countries, while the pressure was now on tropical and subtropical wetlands, it said.

The Sukhdev report noted that the current focus by economists and governments on economic growth as measured by gross domestic product failed to take key aspects of the economy into account.

'GDP growth does not capture many vital aspects of national wealth and wellbeing, such as changes in the quality of health, the extent of education, and changes in the quality and quantity of our natural resources,' it said.

The Sukhdev report aims to create a framework in economic theory to evaluate ecosystems that engages 'end-users' and to provide a policy toolkit for policy makers and administrators.

Sustainable development and better conservation of ecosystems and biodiversity needed to be placed on a basis of sound economics, it said.

The ninth conference of the parties to the Convention on Biological Diversity (CBD) began on May 19 and is in its final, political, phase culminating in the issuing of a conference document on Friday.