Climate intervention
Marine Cloud Brightening
Definition
Marine cloud brightening is a proposed solar geoengineering method, first articulated in its modern form by John Latham in 2008, in which fine sea-salt particles are sprayed into marine stratocumulus clouds to increase their droplet number and albedo (the Twomey effect), reflecting more sunlight to space. Modelling suggests increasing cloud albedo by roughly 6% in susceptible regions could offset the radiative forcing of doubled CO2.
References
Supports definition and framing.
Supports definition and framing.
Overview
What it means
Ship tracks — brighter cloud lines behind vessels — are an inadvertent analogue demonstrating the physics. MCB is researched for potential regional applications, such as cooling coral reefs during bleaching events.
How it is used
Currently confined to modelling, laboratory work and small field experiments (e. g. , in Australia and previously California); it raises governance questions about unilateral deployment and termination effects.
Why it matters
MCB illustrates both the promise and the governance dilemmas of climate intervention: potentially fast, regional cooling, but with uncertain side-effects and no agreed international rules.