A scientist at the University of Edinburgh says that a fleet of water-borne cloud makers could help reduce global warming. The unmanned sailing ships would patrol the oceans, spraying tiny droplets of seawater into existing clouds in order to enlarge and thereby whiten them – bouncing more radiation back into space and cooling the atmosphere in the process.
It is claimed that a change in the brightness of marine clouds could cool the earth enough to compensate for the increase in man-made carbon dioxide over the last century.
The ships would operate in a 1500-strong fleet and rotary-sail technology would ensure not only that the vessels received all the power they needed from wind and seawater, but that they could easily be operated remotely by computer.
Dr Stephen Salter says the seas off Namibia, California and the Southern Ocean are particularly well suited to the concept. He claims the effect could be applied locally, to cool down the Arctic or the seas around coral reefs.
A spokesperson for the Environmental Transport Association (ETA) said: “There are many groups around the world working on technological fixes to the problem of global warming, and whilst most appear beautifully simple, none is proven and changes need to happen now – there is no substitute for a dramatic reduction in the amount of fossil fuel we consume.”
What is a rotor ship?
A rotor-powered ship replaces conventional sails with spinning rotors. It works because a spinning body in a moving airstream experiences a force perpendicular to the direction of the airstream. In the case of the Dr Slater’s design, propeller-like turbines in the water beneath the ship power both the spinning rotors and the droplet-generator.
In 1926, a rotor-ship crossed the Atlantic, and whilst the technology did not catch on at the time, the high price of oil has prompted German energy company, Enercon to develop and this month launch the first rotor-powered cargo ship (pictured right).
How are clouds made artificially?
In this case, seawater is forced through an incredibly fine mesh to produce a mist of droplets less than one micron wide, known as cloud condensation nuclei. These ‘seeds’ are the particles around which water vapour coalesces to form rain.
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