Geoengineering 'may be only answer to global warming'

Risky climate-changing technologies may offer the only hope of saving the world from environmental Armageddon if global warming is allowed to run out of control, it has been claimed.

Risky climate-changing technologies may offer the only hope of saving the world from environmental Armageddon if global warming is allowed to run out of control, it has been claimed.


Governments should start looking seriously at far-fetched concepts such as artificial "trees", cooling the planet by spraying chemicals into the upper atmosphere, and shields in space, a panel of leading scientists said. "Geoengineering" solutions could provide a vital insurance policy if cuts in greenhouse gas emissions fail to hold back climate change and sea level rises, the experts said in a report.


They might have to be employed in the event of a crisis caused by run-away global warming effects, said the scientists. Such scenarios include the Greenland ice cap collapsing and causing a massive surge in sea levels, or huge amounts of methane trapped in Siberian permafrost suddenly being released into the atmosphere.


Methane is a greenhouse gas 20 times more powerful than carbon dioxide.

But the scientists warned that none of the technologies should be seen as a "quick fix" for the problem of global warming and their irresponsible use could have "catastrophic consequences".


They envisaged starting off an international geoengineering research programme with an investment of £100 million a year. Britain's contribution would be £10 million a year - about 1 per cent of what the country spends on new engineering technology.

The experts spent a year investigating the feasibility, affordability, and political and social impacts of geoengineering technology.


Their report, published by the Royal Society, Britain's leading academic institution, focused on two main approaches - Carbon Dioxide Removal (CDR) and Solar Radiation Management (SRM). The first addresses the root of the problem by taking carbon dioxide out of the atmosphere. It includes technologies such as artificial "trees" that suck the gas from the air, exploiting natural reactions between carbon dioxide and rocks and minerals, and growing new forests. However, no CDR techniques are yet known to be effective at an affordable cost, and they only work over very long time scales.


Solar Radiation Management techniques aim to lower temperatures by reflecting the Sun's energy away from the Earth. One cheap and effective option, mimicking the effects of a volcanic eruption, would be to spray sulphate particles into the upper atmosphere.


The potential of these "stratospheric aerosols" was demonstrated in 1991 when the volcano Mount Pinatubo erupted in the Philippines, pouring out large quantities of sulphates. The following year global temperatures cooled by 0.5C. Had the chemical particles from the eruption remained in the atmosphere, the Earth could have cooled by as much as 3C, said the scientists. This would be enough to offset a doubling of carbon dioxide emissions.


Such a solution would have a truly global impact but absolutely no effect on carbon dioxide levels or ocean acidification, said the report. In addition there could be unforeseen and potentially dangerous side effects which would be felt around the world.


Other SRM techniques examined by the scientists included placing reflective shields in orbit around the Earth, and artificially increasing the brightness of clouds using fine particles of sea salt from the oceans.


Some ideas, such as painting the roofs of houses white and promoting the growth of carbon-absorbing algae in the oceans, were found to be of little practical use.

Professor John Shepherd, who chaired the Royal Society's geoengineering working group, said: "It is an unpalatable truth that unless we can succeed in greatly reducing carbon dioxide emissions we are heading for a very uncomfortable and challenging climate future, and geoengineering will be the only option left to limit further temperature increases.


"Our research found that some geoengineering techniques could have serious unintended and detrimental effects on many people and ecosystems - yet we are still failing to take the only action that will prevent us from having to rely on them. Geoengineering and its consequences are the price we have to pay for failure to act on climate change."


He added: "None of the geoengineering technologies so far suggested is a magic bullet, and all have risks and uncertainties associated with them. It is essential that we strive to cut emissions now, but we must also face the very real possibility that we will fail. If plan B is to be an option in the future, considerable research and development of the different methods, their environmental impacts and governance issues, must be undertaken now.


"Used irresponsibly or without regard for possible side effects, geoengineering could have catastrophic consequences similar to those of climate change itself. We must ensure that a governance framework is in place to prevent this."

International agreements and systems of regulation would be needed if such technologies were to be introduced, said the scientists.


Most currently only existed in the form of paper concepts or laboratory experiments, they said. At the end of the day, whether any of them were put into practice depended on their acceptability both to governments and the public.

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