BANGKOK - There's no shortage of ideas for high-tech measures to combat global warming: develop clean biofuels made of corn or palm oil, build more nuclear power stations or bury harmful carbon emissions in underground vaults.
But those are the last solutions many environmentalists want to hear about.
For the green lobby pushing this week for forceful action at a U.N. conference on limiting the rise in global temperatures, such answers either cost too much, delay an inevitable weaning from fossil fuels or get in the way of the real solutions, such as renewable energy and greater efficiency.
"There are a lot of technologies that are mentioned ... that are not exactly the most sustainable options," said Catherine Pearse, international climate campaigner for the Friends of the Earth environmentalist group. "We may be replacing one existing problem with new ones."
Finding effective mitigation measures at the meeting in Bangkok is crucial to ensuring the world is able to cut greenhouse gas emissions and keep the atmosphere from warming more than 3.6 degree.
The Intergovernmental Panel on Climate Change, the U.N. network of 2,000 scientists that has produced two landmark reports on global warming this year, was working on a third study -- this one on mitigation measures -- for release on Friday.
A draft of the report features a lengthy list of possible solutions: improved energy efficiency like hybrid vehicles, renewable sources such as solar- and hydropower, cleaner-burning coal and biofuels, reforestation and even nuclear energy -- an option the United States is pushing to give greater emphasis in the final document.
But not all the proposals are equal, environmentalists argue, saying some -- such as nuclear power -- are dangerous, while technologies such as renewable energy sources are not given proper emphasis.
The green lobby is a varied group, but the lion's share of them insist concern over global warming should not lead to increased reliance on nuclear energy.
"For us, nuclear power is definitely not a solution. It's dangerous, it's expensive," said Shailendra Yashwant, a climate and energy campaign manager for Greenpeace. "The costs involved, the dangers involved, they want us to forget all of that."
Even less controversial energy sources have generated opposition among environmental groups.
Biofuels are seen by many as an excellent option. The U.S. Congress, for example, is working on a proposal that would increase production of biofuels, predominantly ethanol, by seven times by 2022. Such fuels are made from corn, palm oil and other agricultural products.
But where some see a profitable way to wean the planet from gasoline, others see even more damage to the environment.
The rapidly increasing interest in biofuel production is already driving corn prices beyond the budgets of the world's poor and leading to an acceleration of deforestation -- one of the causes of global warming -- as lands are cleared to grow oil palm in places like Indonesia, critics say.
"You should not be cutting down forests to create fuels," said Yashwant.
Coal is increasingly taking center stage in the global warming debate, for good reason: global hard coal production has increased nearly 80 percent from 1980 to 2005, the World Coal Institute says. China is by far the largest producer.
Coal, however, is an extremely dirty fuel, and scientists are trying to develop technology to capture the carbon emissions before they are released into the atmosphere, and store them underground or under the ocean.
But critics argue the technology is as yet unproven, the storage vaults could leak and that money spent on developing such measures -- which would prolong the world's reliance on fossil fuels -- would be better spent making solar and wind power viable.
Not everyone in the green lobby is opposed to so-called carbon storage. Such a system could be a stopgap measure to cut emissions while the globe converts to non-carbon fuels over the next 50 year, said Stephan Singer of the World Wildlife Fund.
"It's like an emergency exit," Singer said of the storage idea. "The world is running on coal ... If you look at the U.S. and China, you see it."
The United States and others are arguing for a wide diversity of mitigation measures and are especially keen on steps that reap profits and high-tech spin-off -- such as biofuels -- and avoid cutting into economic growth.
Still, some say the world needs to decide which measures should be pursued -- otherwise governments will take the cheapest, easiest paths rather than the ones that would cut carbon emissions the most.
"This is a report that is moving away from the science and moving into the political," said Pearse. "They're looking for a silver bullet, and we don't believe that such a thing exists, not for climate change."
