Natural gas, including non-traditional shale gas, should play a major role in cutting greenhouse gases, protecting forests and improving the health and living standards of the world's poor, the co-head of a U.N. sustainable energy program said on Monday.

Without it, the U.N.'s Sustainable Energy for All Initiative will have difficulty meeting goals of ensuring universal energy access, doubling the world's share of renewable energy and doubling the rate of improvement in energy efficiency by 2030, Kandeh Yumkella, co-head of the initiative, told Reuters.

"You can't save the forest if you don't have gas," Yumkella, a native of Sierra Leone, said in an interview on the sidelines of a global development meeting in Rio de Janeiro.

"It's one of the solutions we need to reduce deforestation and reduce the two million people who die every year because of indoor air pollution because they use firewood."

Yumkella, who is also the head of the U.N. Industrial Development Organization, understands his support for natural gas is controversial, but finding the estimated $43 billion a year needed to provide electricity by 2030 to 1.3 billion people, half the number without it today, will be near impossible.

Many attending the U.N. conference, known as the Rio+20 as it comes two decades after a landmark Earth Summit in the city, see the inclusion of natural gas in the initiative as problematic.

Natural gas is a non-renewable hydrocarbon the burning of which creates carbon dioxide, a greenhouse gas believed to cause global warming.

"Yumkella is a great man, but his panel is dominated by people who speak for big power industries," Pasco Sabido, climate adviser to environmental group Friends of the Earth Europe, said in an interview.

Yumkella's panel, picked by U.N. Secretary General Ban Ki-moon, is co-chaired by Chad Holliday, chairman of Bank of America, Chen Yuan, chairman of the China Development Bank, and Carlos Ghosn, chairman and chief executive of Renault-Nissan

Sabido believes Yumkella's goal to generate more energy and electricity where poor people live, using solar power and fuels made from human and animal waste and other biomass, will be sidetracked. This will hurt the poor, he said.

"Gas may be good as a stop-gap measure," said Carlos Rittl of the World Wildlife Fund (WWF). "But it's not a long-term solution. We need to really move away from old energy sources."

Yumkella, who has consulted governments, industries and non-government groups such as the WWF, says it is hard to push any solution for climate change.

On the agenda

Mistrust has grown around environmental issues after many countries failed to meet promises made after the 1992 Earth Summit and in the Kyoto Climate Change Protocols, he said.

Rich countries have worried that changes in energy policies will make them poor while poor countries worry that the policies will prevent them from rising out of poverty.

"Any global energy initiative that doesn't put people first is bound to fail in addressing energy poverty," said Lidy Nacpil, a coordinator for the Jubilee South Asia/Pacific Movement on Debt and Development.

"Instead of looking at community owned and managed energy, it pushes more privatization."

Yumkella feels the criticism comes with the subject.

"At least we've finally managed to get energy on the agenda," he said. "Before this any talk at the U.N. of energy got sidetracked into the geopolitics of oil and gas."

Oil and gas development is essential, he said, especially as concern about energy security has led to discoveries of new resources in places such as his home, Sierra Leone, and other African nations, the region with the lowest access to electricity and clean energy.

"Think about the world 40 years from now," he said. "Is Africa going to ship their resources to the developed world for the rich guys to have their SUVs and air conditioning and all these other folks remain poor? That's a recipe for insecurity."

At the same time he praises the development of shale gas in the United States, an abundant resource that has helped the world's biggest polluter slash carbon emissions - replacing coal with cleaner gas - and making energy cheaper.

"We welcome new sources of energy, in fact you have to give the Americans credit," Yumkella said. "Fifteen years ago they decided to invest in new technology."

"Shale gas is doable if the research and development is done and it is less polluting than other forms ... At the same time we need to safeguard, we need to make sure the technologies don't do collateral damage."

Friends of the Earth's Sabido called such a position dangerous because shale gas exploitation threatens fresh water supplies and disrupts remote communities.

As for existing oil and gas technologies, much needs to be done to prevent waste and pollution. Some measures could help give the poorest energy, he said.

Part of the initiative calls for drastically reducing the amount of gas that is burned off, or "flamed", and wasted for lack of a market or pipelines.