This was a summer of record heatwaves and crushing drought — and experts are warning that it's only going to get worse from here on out. So a number of scientists are calling for dramatic solutions — including "cloud brightening," a process of blasting salt water into the sky to form massive, long-lived clouds.
This notion is nothing new, but a new paper insists that it's an idea whose time has come — and we should start testing the concept immediately.
In a new paper published in the Philosophical Transactions of the Royal Society, atmospheric physicist Rob Wood is proposing that an experiment be conducted on a small scale — a strategy that could yield important scientific insights while alleviating some of the anxieties associated with geoengineering proposals. And 25 other scientists have endorsed the idea.
According to theory (and computer models), seeding marine stratocumulus clouds with copious amounts of tiny sea water particles could significantly enhance cloud droplet number concentration, and thereby cloud reflectivity and longevity. Assuming that this could be done on a large scale, the result would be a cooling effect.
Wood and his colleagues are proposing a three-stage approach, to asses the feasibility of cloud brightening.
Initially, the project would start by deploying sprayers on a ship or barge to ensure that enough salt water particulate can be blasted high enough into the sky. In turn, a plane equipped with sensors would monitor the physical and chemical characteristics of the particles and how they disperse.
During the second phase, scientists would more closely study how the cloud develops and how long it persists. And during the last phase of the experiment, the team would send out about five to 10 ships across a 100 kilometer expanse to create clouds large enough to be tracked by satellites.
By conducting the experiment in this way, Wood contends there would be minimal impact to the environment. In theory, given the small scale, the clouds would only last for a few days.
Interestingly, Wood and his team are not making any grand claims about the long-term potential of cloud brightening to stave-off global warming. They see their experiment as a very preliminary scientific endeavor to simply assess feasibility and safety.
"I would rather that responsible scientists test the idea than groups that might have a vested interest in proving its success," said Wood through a release. The danger with private organizations experimenting with geoengineering is that "there is an assumption that it's got to work."
The study concludes by cautiously noting:
We stress that there would be no justification for deployment of [marine cloud brightening] unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favor of such action.
You can read the entire paper at Philosophical Transactions of the Royal Society.