To cool planet, researchers propose spraying particles into marine clouds

SAN FRANCISCO - A group of researchers at the University of Washington is investigating the idea of marine cloud brightening as a strategy to offset global warming. As a short-term measure for a possible future emergency situation, the strategy involves spraying saltwater into clouds above oceans to boost their capacity to reflect sunlight.

In a paper published in the journal Earth's Future, two UW researchers, including lead author Rob Wood, a professor of atmospheric sciences, say small-scale tests of marine cloud brightening would also help answer scientific questions about clouds and aerosols' possible role to help cool the planet.

One of the biggest uncertainties in climate models is the clouds, which reflect sunlight in unpredictable ways. Water droplets can only condense on airborne particles, such as smoke, salt or human pollution. When the air contains more particles, the same amount of moisture can form smaller droplets, which creates whiter, brighter, more reflective clouds.