A summit of environmental leaders and politicians has called for an urgent move towards a global green economy in order to achieve sustainable development over the next half century.

Low-carbon technology, green infrastructures, investment in renewable energy and sustainable agriculture are essential in combating climate change, poverty and water shortages, said participants in the summit convened by WWF to mark the global conservation organization's 50th anniversary.

EU Environment Commissioner Janez Potocnik told participants that unless biodiversity is adequately protected the consequences would be "catastrophic."

"Biodiversity and ecosystem services must be protected, valued and adequately restored," said Commissioner Potocnik. "It's essential for human well being and in our own self-interest."

"If we do not preserve ecosystems we will push biodiversity over the tipping point beyond which changes become irreversible and possibly even catastrophic," he warned. "It is an irrefutable fact that global consumption and use of resources is the biggest factor in a sustainable future."

Together with leaders from Asia and Europe, Commissioner Potocnik took part in a roundtable, Public Sector Voices on Conservation in the Next Half-Century, where they envisioned the state of the planet in 50 years' time.

Chairing the debate, WWF International President Yolanda Kakabadse said, "We are here to celebrate 50 years of WWF - but we want to look forward, not back. What is the next half century going to bring in terms of water, food and life on Earth?"

Bhutan's Minister of Agriculture and Forests, Dr. Pema Gyamtsho pledged that within 10 years, Bhutan would be the world's first totally organic country, as part of its drive towards sustainability.

He said water security is the biggest challenge facing Bhutan, a challenge that can only be solved through global action.

"What happens in the Himalayas and South Asia is going to impact all of us," warned Dr. Gyamtsho. "Can we afford to wait until 2050 to limit temperature rises to two degrees celsius? Two degrees will be too much and 2050 will be too late."

"We need to act now," he urged. Many areas are already suffering shortage of drinking water."

Norwegian Environment Minister Erik Solheim spoke of the urgent need to put real economic value on ecosystems and natural resources to help stop widespread deforestation.

"We must come to a situation where there is an economic benefit for the sustainable use and conservation of natural resources," said Solheim.

"The big success story is Brazil where deforestation has been reduced by 70 percent in seven years - by far the biggest factor in fighting climate change. NGOs must encourage governments to take risks and support those politicians who do do something."

Monique Barbut, CEO of the Global Environment Facility, warned that any proposed global green investment fund to fight climate change should not attempt to replace or duplicate existing environmental and development finance.

"Today there are more than 230 overseas development funds which lead to fragmentation and more overheads," said Barbut. "We should not be trying to build again another poorly coordinated system which is not going to work. I do not believe we need a new institution or a new bureaucracy."