GENEVA (Reuters) - “Climate engineering” projects, such as spraying seawater into the sky to dim sunlight, would be a more effective brake on global warming than increasing taxes on energy, a group of economists said on Friday.

Led by Bjorn Lomborg, a Danish statistician and author of “The Skeptical Environmentalist,” a book which questioned orthodox environmental views, the group ranked “cloud whitening” as a top option in combating climate change.

“Climate engineering could provide a cheap, rapid and effective response to global warming,” the economists said.

Lomborg’s panel ranked research into “marine cloud whitening technology” -- having boats spray seawater droplets into the sky to create clouds -- as the best of 21 ideas reviewed.

They ranked more research into clean energy such as solar and wind power second, ahead of research into spewing tiny dust-like particles high into the atmosphere to block sunlight and research into burying greenhouse gases.

Among the least promising solutions, the group said that: “carbon taxes would be an expensive, ineffective way to reduce the suffering from global warming.”

Many governments favor schemes that would place a price on carbon emissions, which would mean higher energy taxes.

“We should look at climate engineering as a fix for the first 50 to 100 years,” Lomborg told Reuters of the findings, meant as alternative advice to governments working on a new U.N. climate treaty due to be agreed in Copenhagen in December.

“Research into green energy is what is going to fix the climate in the long term,” he added.

LARGELY SPECULATIVE?

Earlier this week, Britain’s main science academy, the Royal Society, recommended more research into climate engineering as an insurance policy but said it was not an alternative to cuts in emissions of greenhouse gases.

And the Intergovernmental Panel on Climate Change, the scientific group that advises the United Nations, concluded in a 2007 report that technologies such as blocking sunlight “remain largely speculative and unproven, and with the risks of unknown side-effects.”

“We found that climate engineering has great promise,” Thomas Schelling, a Nobel Prize winning U.S. economist who was in Lomborg’s group, said in a statement. “Even if one approaches it from a skeptical viewpoint, it is important to invest in research to identify the limitations and risks.”

Others economists in the group were Norwegian Finn Kydland and American Vernon Smith, both Nobel economics laureates, as well as Nancy Stokey from the University of Chicago and Jagdish Bhagwati from Columbia University.