Using a fleet of 1500 wind-powered ships that cruise the oceans autonomously, spraying massive plumes of salt water into the air, we could reverse the effects of global warming within years. So says John Latham, a researcher at the National Center for Atmospheric Research in Boulder, U.S., who has worked with colleagues to develop a fairly extensive plan for reengineering the climate. How would salt water spray lower the temperature of the oceans enough to make a difference? Latham explains that it's all about making clouds more reflective. When the salt spray gets taken up into the clouds, the salt crystals allow more drops of water to form. And a cloud with more water in it can reflect more sunlight. Ultimately, Latham hopes, this means that less sunlight will reach Earth and allow the oceans to cool down. If his plan were put into practice right away, it's possible we could prevent the Arctic ice sheet from breaking up, and keep those giant ice shelves from crumbling in Antarctica. As the cooled ocean currents circulate throughout the world, global temperatures will lower too. According to Physics World:

Latham maintains that his group's idea is not pie in the sky and that its feasibility is supported by two of the world's leading computer climate models, as well as recently obtained experimental cloud data. He points out that, unlike rival techniques, the system could be used to vary the degree of cooling as required and could be switched off instantaneously if needed. However, he adds more research must be done to find out a number of unknowns - such as exactly what fraction of spray droplets will reach the clouds - and to establish that the technique would not create any harmful climatic side effects. More work must also be done on the spray technology, he says.


Before you get excited, futurist Jamais Cascio, who writes a lot about geoengineering, has some words of warning:

A couple of really important factors, worth keeping in mind when evaluating these kinds of proposals: 1) Albedo-changing geoengineering (like the water spray, or stratospheric sulphate particles) is a symptom-reduction treatment, not a cause-reduction treatment. This means that if you stop the geoengineering — and you haven't been reducing carbon outputs — all of the heat comes back, and there's even a "bounce" effect where it can get warmer faster than it would have otherwise. 2) Geoengineering of this sort does nothing about carbon, but excess carbon does more than just warm the air. Ocean acidification is probably the biggest problem, causing coral extinctions, diatom extinctions (HUGE foodchain implications), and similar nastiness. Geoengineering is useful if it's coupled with carbon-reduction, since it can slow the onset of some of the warming-related catastrophes. It's not a cure or a solution for global warming, though. It's a cough-suppressant — can be ideal for letting you sleep and get rid of your flu, but can make the flu stick around longer if all you do is use it to get through a work day.


Cloud-Seeding Ships Could Combat Climate Change [via Physics World] Thanks, Ethan!