Could Salting Clouds Buy Precious Time in Fight Against Global Warming?

Once considered a risky last resort, geoengineering is becoming more accepted as a possible way to slow down global warming – but that doesn’t mean some of the ideas scientists are coming up with don’t sound downright kooky to the layman. One proposal involves lightening clouds with salt to improve their ability to reflect sunlight.

Scientist John Latham suggested that increasing the number of droplets in maritime layer clouds (stratocumulus), which cover a third of the ocean, could significantly increase their reflectance.

From BBC News:

The water droplets in clouds reflect solar radiation back to space. And the numbers of droplets they contain are largely controlled by the number of cloud condensation nuclei (CCN), such as specks of dust.

Many of these nuclei are produced over the land. Land-locked clouds therefore contain many hundreds of cloud droplets per cubic centimetre, whilst clouds that form over the sea contain substantially fewer.

Generally, the more droplets that are present in a cloud, the smaller they are. For a given mass of water in a cloud, clouds with smaller droplets tend to be whiter.

So the proposal is to inject a fine spray of sea salt from the ocean surface into the clouds; to artificially increase the number of drops, reduce their size and increase the reflectance of the clouds, making them whiter.

The cooling that could result from this experiment could buy us 25 years in the battle against global warming – certainly, a lot of precious time to make other changes that could improve the outlook. But this method will take quite a bit of testing to get it just right, including experiments to determine the ideal size of the sea-salt nuclei. Research is expected to cost about $10 million.

So how exactly would we go about salting clouds? Edinburgh University scientist Stephen Salter (yes, that’s really his name) suggested a fleet of “cloudseeders”, wind-powered yachts that would inject the clouds with sea salt.

Link [BBC News]
Photo credit: John McNeill via WFS.org

Related Posts:

Can Cloud Seeding Prevent Global Warming?
Global Warming Could Cause Tilt in Earth’s Axis
New CO2-Eating Cement Could Help Fight Global Warming
New Vivace Energy Technology Harnesses Vortex Hydro-Energy
Climate Change Researchers Discover Carnivorous Sea Squirt 4,000 Meters Underwater