What is it?
Cloud brightening, also known as “cloud reflectivity enhancement,” is a geoengineering technique that aims to lower the earth’s albedo—the extent to which an object diffuses light a particular source. Confused yet? Well, in simpler terms, the technique aims to make clouds “whiter” by spraying ocean water into the atmosphere, rendering it more reflective to sunlight in an effort to curb modern day global warming.
Compared to many of the other methods currently being investigated by geoengineers, cloud brightening is relatively simple to design and implement. Ships with appropriate equipment can be deployed quickly and cheaply for testing, and mass production after that would not be difficult either. Moreover, the effect is fully reversible, as the sprayed water particles would eventually simply drift back down to the ocean.
What problem does this solution address?
Obviously, cloud brightening can be used to curb the effects of global warming, but its biggest advantage is the relatively cheap cost and ease of implementation. By spraying the atmosphere over the ocean with ocean water, researchers aim to render the skies more reflective and therefore send more of the sun’s radiation back into space. Additionally, the technique will be more effective over the ocean where there is much less dust and pollutants in the air to impede the process. In fact, an expert panel concluded this past September that “a total of about $9 billion spent developing marine cloud whitening technology might be able to cancel out this entire century’s global warming.”
What are the possible effects?
As with any planetary-scale climate change project, there are some risks involved with the plan. There might be some minor naval hazards involved as the plan calls for well over 1000 unmanned ships to roam the Earth’s oceans. The increased formation of clouds over already stormy seas might also be a cause for concern for various nautical enterprises, including commercial trading ships and military vessels.
Is it a good idea?
More so than other techniques, cloud brightening seems to have a decent amount of support behind it. One proposed scheme would use a fleet of about 1500 unmanned rotor ships that would spray ocean water into the skies in an effort to thicken clouds and make them more reflective. According to research, this method “can give >3.7W/m2 of globally-averaged negative forcing, which is sufficient to reverse the warming effect of a doubling of CO2.” Due to the relatively cheap cost estimates put forth by experts, this is a technique that warrants attention from governments around the world.