The cloud ships that could cancel out effects of global warming this century for £5.3bn.
Special ships that create clouds by spraying seawater into the air could be the most cost effective way of tackling climate change, new research has found.
The technique, known as marine cloud whitening, would create clouds above the Pacific Ocean that would have a cooling effect by reflecting sunlight away from Earth.
A wind-powered fleet of nearly 2,000 ships would criss-cross the sea, sucking up sea water and spraying it upwards through tall funnels.
'When you spray saltwater into the air, you create nuclei that cloud condenses around, creating bigger and whiter clouds, thus bouncing more sunlight back into space,' said David Young from the think-tank that commissioned the study.
Lonely as a cloud:
A flotilla of 1,900 ships would cruise the Pacific creating clouds to reduce ocean warming
The paper by Professor Eric Bickel and Lee Lane looked into the costs of potential climate engineering projects. It was commissioned by the Copenhagen Consensus Center that advises governments how to spend aid money.
It found that cloud whitening would effectively wipe out the effects of climate change this century for no more than £5.3billion. This is a fraction of the £150billion that leading nations are considering to spend cutting CO2 emissions each year.
It is also more than 25 times cheaper than the £140billion cost of developing the alternative of stratospheric aerial insertion. This scheme would mimic the cooling effect of volcanoes by creating a hazy layer of particles like soot, which would scatter and absorb sunlight creating a cooling effect for at least a year.
The final suggestion considered was the plan to deploy tiny sunshades into space to shield Earth from some of the Sun's rays. However, this was discounted due to its astronomical cost of £236trillion.
The authors also compared the overall cost of the schemes with the cost benefits that reducing temperatures would have. These would include the human costs on health, impact on different industries such as agriculture and tourism and the effect of flooding.
They found every £1 spent on stratospheric aerosols would reap £15 of benefits, however every £1 spent on cloud whitening would bring £2,000 of benefits.