Bonn: 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 German city of Bonn.

Development economist Pavan Sukhdev, who is head of Deutsche Bank's Global Market Centre in London, put the annual loss to the world economy at up to 3.1 trillion euros ($4.8 billion) 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 percent.

"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.