Crank of the Week - September 1, 2008 - John Latham

For a change this week we have left the realm of political inanity and selected a new Crank of the Week from the ranks of those who should know better—scientists. This week's crank is John Latham of the National Center for Atmospheric Research in Boulder, Colorado, for suggesting the creation of a fleet of 1500 robot sailing ships to combat global warming. These autonomous vessels would sail the world's oceans creating artificial cloud cover by spraying salt water into the air.

The 300-ton unmanned ships would be powered by the wind, but would not use conventional sails. Instead they would be fitted with a number of 100 ft high, 8 ft in diameter cylinders known as Flettner rotors. The continuous rotation of these cylinders would generate a force perpendicular to the wind direction, propelling the ship forward if it is oriented at right angles to the wind.

Illustration by John MacNeill

The scheme relies on the “Twomey effect”, which says that increasing the concentration of water droplets within a cloud raises the overall surface area of the droplets and thereby enhances the cloud’s albedo. Albedo is the measurement of how reflective an object, like a planet, is. The more reflective Earth is the more solar radiation is reflected back into space, reducing the Sun's heating effect. By spraying fine droplets of sea water into the air, the small particles of salt within each droplet act as new centers of condensation: the more condensation the more low cloud cover, the more low cloud cover the higher Earth's albedo, the higher Earth's albedo the lower Earth's surface temperature—global warming solved.

Latham and colleagues, writing in the Philosophical Transactions of the Royal Society A, are the latest bunch of scientists to suggest cloud making as a way to cool our planet. As such they join a long line of scientists to suggest wacky solutions to mankind's perceived problems. Quoting from the article:

Analytical calculations, cloud modelling and (particularly) GCM computations suggest that, if outstanding questions are satisfactorily resolved, the controllable, globally averaged negative forcing resulting from deployment of this scheme might be sufficient to balance the positive forcing associated with a doubling of CO2concentration. This statement is supported quantitatively by recent observational evidence from three disparate sources. We conclude that this technique could thus be adequate to hold the Earth's temperature constant for many decades.

Fitting right in there with suggestions for orbiting swarms of “space mirrors” and plans to dump thousands of tons of powdered iron into the waters around Antarctica, this is yet another example of how thin the line is between “out of the box” thinking and “around the bend” ideas. Not that it is bad for scientists to treat such enterprises as thought experiments; scientists should dream big dreams. The real problem is when such ideas get sized upon by the scientifically ignorant masses of eco-activists, news reporters, and politicians.

Writing in another A journal article, titled “Geoscale engineering to avert dangerous climate change,” Brian Launder and Michael Thompson put it this way: “Frustrated by the delays of politicians, scientists (including some at the highest levels) have for a number of years been proposing major 'last minute' schemes that might be needed if it were suddenly shown that the climate was in a state of imminent collapse. These geo–scale interventions are undoubtedly risky: but the time may come when they are universally perceived to be less risky than doing nothing.” Fortunately that time has not yet come and, until it does, such wacky high-risk plans qualify their authors as Cranks of the Week.