A Pathway to Quantifying Marine Cloud Brightening as a Climate Intervention Mechanism

Abstract:

One of the leading proposed mechanisms for intentionally cooling climate is Marine Cloud Brightening (MCB). The concept is to add sea salt to low marine clouds, increasing the number of droplets in the clouds and thereby increasing their brightness, reflecting more sunlight back to space, and cooling climate. This idea is based on observations of cloud brightening induced by the inadvertent emission of pollution particles, most notably in “ship tracks”, where cargo ship emissions can lead to visibly brighter streaks of clouds in the marine environment. This presentation will discuss the scope of research needed to determine whether low marine clouds could be intentionally brightened sufficiently and with enough predictably and reliably to produce significant climate cooling and what the local, regional and global impacts of doing so would be. It will also touch on existing mechanisms for oversight of experimental-scale tests of intentional cloud brightening, which we argue are essential to determining whether MCB would be an option for effective climate intervention.