could damage the planet in the long-term

From sending mirrors into space to injecting sulphur into the atmosphere, scientists have developed an increasing array of techniques to battle climate change.

But this type of ‘climate engineering’ – which involves manipulating the natural processes after emissions have been released – is only a quick and cheap fix, according to a new report.

In the long run, such drastic geoengineering measures are 'irrational and irresponsible' and could ultimately damage the planet, a US panel of scientists has said.

From aerosols iron fertilisation of the sea (left) to cloud seeding and greening deserts (right), scientists are conjuring up an increasing array of geoengineering techniques to battle climate change. But this type of ‘climate engineering’ could ultimately damage the planet, a new report says

However, the scientists add that some geoengineering concept should be tried out in small projects to learn more about the risks.

'There is no substitute for dramatic reductions in greenhouse gas emissions to mitigate the negative consequences of climate change,' said the National Research Council in a two-part report on proposed climate-intervention techniques.

'If society ultimately decides to intervene in Earth's climate, any actions should be informed by a far more substantive body of scientific research, including ethical and social dimensions, than is presently available.'

The Washington-based panel urged against 'albedo-modification technologies, which aim to increase the ability of Earth or clouds to reflect incoming sunlight,' saying they 'pose considerable risks and should not be deployed at this time.'

The Washington-based panel urged against 'albedo-modification', which aim to increase the ability of Earth or clouds to reflect incoming sunlight,' saying they 'pose considerable risks and should not be deployed

Such techniques would only temporarily mask the warming effect caused by high CO2 concentrations, and present serious known and possible unknown environmental, social, and political risks, said the report.

POTENTIAL SIDE EFFECTS OF FIVE GEOENGINEERING STRATEGIES Afforestation: This technique would irrigate deserts, such as those in Australia and North Africa, to plant millions of trees that could absorb carbon dioxide. Drawback: This vegetation would also draw in sunlight that the deserts currently reflect back into space, and so contribute to global warming. Artificial ocean upwelling: Engineers would use long pipes to pump cold, nutrient-rich water upward to cool ocean-surface waters. Drawback: If this process ever stopped it could cause oceans to rebalance their heat levels and rapidly change the climate. Ocean alkalinisation: This involves heaping lime into the ocean to chemically increase the absorption of carbon dioxide. Drawback: Study suggests it will have of little use in reducing global temperatures. Ocean iron fertilisation: The method involves dumping iron into the oceans to improve the growth of photosynthetic organisms that can absorb carbon dioxide. Drawback: Study suggests it will have of little use in reducing global temperatures. Solar radiation management: This would reduce the amount of sunlight Earth receives, by shooting reflective sulphate-based aerosols into the atmosphere. Drawback: Carbon dioxide would still build up in the atmosphere. Advertisement

Carbon dioxide removal is better understood 'but current technologies would take decades to achieve moderate results and be cost-prohibitive at scales large enough to have a sizeable impact,' it added.

'Direct air capture of carbon is an immature technology with only laboratory experiments carried out to date and demonstration projects in progress,' the report said.

'Technologies for storing the captured carbon are at an intermediate stage, but only prototypes exist and are not at the scale required for significant sequestration.'

Other techniques such as forest restoration and low-till agriculture are 'mature, readily deployable technologies with well-known environmental consequences,' the report added.

Afforestation, for instance, would irrigate deserts, such as those in Australia and North Africa, to plant millions of trees that could absorb carbon dioxide.

However, this vegetation would also draw in sunlight that the deserts currently reflect back into space, and so contribute to global warming.

It follows a similar report last year that found schemes to deliberately manipulate the Earth’s climate could prove useless, and at worst harmful.

Researchers at the Geomar Helmholtz Centre for Ocean Research in Germany used software to test the potential benefits and drawbacks of five different geoengineering technologies.

Their study suggests that even when several technologies are combined, geoengineering would be unable to prevent average surface temperatures from rising more than 2°C (3.6°F) above current temperatures by the year 2100.

‘The long-term consequences and side effects of these methods have not been adequately studied,’ said Dr David Keller from the Geomar Helmholtz Centre for Ocean Research in Kiel, Germany.