GLOBAL - Governments, banks, companies and investors have called for natural capital to be valued and accounted for at Rio+20, the UN Conference on Sustainable Development.

Forty banks, investors and insurers - including Caixa Economica Federal, Caisse des Depots, China Merchant Bank, National Australia Bank, Nedbank, Sovereign and Standard and Chartered, the heads of more than 50 countries and corporations such as Unilever, Puma, Dow Chemical and Mars - voiced commitment to work towards the development of methodologies to value and account for nature's vital role in the global economy.

UK deputy prime minister Nick Clegg, who opened the Natural Capital Dialogue, said: "National governments must move beyond a narrow understanding of wealth.

"Right now, we judge how well a country is doing by looking almost exclusively at the money it makes, ignoring the state of assets like forests or coastal areas - vital natural capital. Only with this sort of joint effort will we start to make the sort of progress needed."

Clegg pointed out that the UK was reforming its national accounts to reflect its natural wealth by 2020.

"I'm delighted that UK businesses are leading the way, too," he said. "Companies such as Marks and Spencer, Aviva and Tesco already report their greenhouse gas emissions, and from April 2013, all businesses listed on the main market of the London Stock Exchange will include this information in their annual reports."

Andrew Mitchell, director of the Global Canopy Programme, one of the three convenors of the Natural Capital Declaration, said: "A tsunami of financial capital is flowing around the world and using up the natural capital upon which our future wealth and security depends.

"This erosion of our collective future makes no sense, and it's time to put our account with nature back in balance. Doing so offers huge opportunity for nations rich in natural assets, and is an essential component of any green growth strategy. It's not about pricing nature, it's about saving ourselves."

Mitchell said the visible engagement of finance sector leaders in this process was a "giant leap forward".

"We may look back on Rio+20 as the moment in history when a global transformation to account for nature in the world economy really gained momentum," he said.

Growing numbers of business leaders are committing to initiatives such as the financial sector's Natural Capital Declaration and the Natural Capital Leadership Compact for the corporate sector, while more than 50 countries are already members of the Wealth Accounting and Valuation of Ecosystem Services (WAVES) initiative.

Paul Polman, chief executive at Unilever, who spoke at the event, highlighted the need for integration of business and finance sector natural capital accounting and valuation.

"The world urgently needs a shift to a more sustainable, equitable form of capitalism, but we cannot do this without the financial sector, whose lending and investment decisions determine whether our natural capital is further depleted or enhanced," he said.

World Bank vice-president for sustainable development Rachel Kyte added: "Rio has provided an opportunity for countries and the private sector to step up their commitment to natural capital accounting and to demonstrate its potential benefits to a global audience.

"There is now overwhelming support for implementation across the world."