John Latham ponders a plan to counter global warming
When MMM’s John Latham first wrote about the idea of tinkering with marine clouds to offset global warming in 1990, he faced some scorn.
Two irate readers berated John’s note on the topic in Nature magazine, contending that society should cut back on carbon dioxide emissions instead of further interfering with the environment.
But with carbon dioxide levels continuing to rise in the atmosphere, John’s research is getting a bit more attention, as are other still-unproven plans that seek to counter global warming.
“I was quite prepared, and still am, for this idea to be viewed as crazy,” John concedes.
John’s idea, which has not been fully tested, is to increase the number of water droplets in about 10% of the world’s marine stratocumulus clouds.
This could be accomplished by bolstering the number of tiny saltwater droplets that act as cloud condensation nuclei, meaning they would serve as centers for the production of additional droplets.
Such a process would make the clouds whiter, increasing their albedo, or ability to reflect solar radiation back into space.
If the clouds’ reflectivity could be boosted by a few percent (which could be amply achieved by doubling the droplet numbers), this would compensate for a doubling of carbon dioxide levels in the atmosphere and, at least in theory, produce a cooling that would compensate for global warming.
The plan could also have the benefit of blocking additional sunlight by increasing the lifetimes of the clouds.
The reason is the added droplets would be small and descend slowly. As a result, it would take longer for them to combine into drizzle or raindrops and fall back to Earth, dissipating the clouds.John hopes to get funding to test the idea within the next couple of years. Such tests could involve a plane seeding marine stratocumulus clouds with particles and then collecting data on the resulting whitening of the clouds.