Over the past decade, there has been increasing scientific discussion about the risks and benefits of intentionally cooling Earth’s surface temperature by increasing the reflectivity of the atmosphere. Two methods have emerged as the most potentially viable.
One method, stratospheric aerosol injection, or SAI, involves dispersing microscopic particles between 7 and 30 miles high in the atmosphere to reflect a small portion of sunlight back into space. The other method, marine cloud brightening, or MCB, involves seeding low-level marine clouds with sea salt particles to make the clouds more reflective and reduce the amount of sunlight that can reach the waters below.
One well-established characteristic of atmospheric particles is that while they reflect a small fraction of incoming sunlight, a much larger portion of sunlight that is not reflected is largely diffused, or scattered forward in different directions. Now, a new NOAA study published in the journal Geophysical Research Letters has found that this diffusion of sunlight from particles in the stratosphere could indirectly make marine clouds thousands of feet below more reflective, or in essence brighter.
