Volcanic leaks point to climate gas storage risks

TRONDHEIM, Norway, July 9 (Reuters) Hundreds of deaths caused by volcanic leaks of carbon dioxide from Cameroon to California are worrying experts seeking ways to bury industrial emissions of the gas as part of an assault on global warming.

Governments and companies are researching how to trap carbon dioxide -- a greenhouse gas released by burning fossil fuels in power plants and factories -- and then entomb it safely in porous rocks deep below ground.

However, they have done little to explain the vast costs and the risk of leaks from projects that could end up burying billions of tonnes of gas and do more to slow global warming than a shift to renewable energies such as solar or wind power.

''There may be massive public resistance, as we've seen with nuclear power'' if governments fail to convince voters that storage is safe, said Bert Metz, co-chair of a 2005 UN report on carbon sequestration.

''Public acceptance...is a possible show-stopper if things are not done properly,'' he told Reuters during a conference of 1,000 researchers into carbon dioxide technologies in Trondheim, Norway.

Carbon dioxide is a non-toxic gas produced by respiration by animals and plants, making up a tiny 0.04 per cent of the air.

Levels are up 30 per cent since the Industrial Revolution and most scientists say the rise is the main spur of global warming.

In pure form the gas can asphyxiate because it is heavier than air and so displaces vital oxygen.

In the worst case in recent decades, 1,700 people died after a catastrophic 1986 release of 1.2 million tonnes of carbon dioxide from the depths of Lake Nyos in Cameroon, according to the International Energy Agency.

Thirty-seven people died from a similar seismic release from Lake Monoun in Cameroon in 1984. In 1979, an explosion at Dieng volcano in Indonesia released 200,000 tonnes of the gas, smothering 142 people on the plain below.

DANGEROUS VENT In April this year, three ski patrol workers died at Mammoth Mountain, California, when they were overcome by carbon dioxide while trying to fence off a dangerous volcanic vent.

''Carbon storage is not risk-free but we think the risks are manageable,'' said Philippe Lacour-Gayet, chief scientist for research and development at Schlumberger oil and gas services group, one of many companies involved in research.

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