Unmanned flights could hold the key to “global dimming”

A consortium of scientists led by the Scripps Institution of Oceanography at the University of California, San Diego, have been using unmanned aerial vehicles, or AUAVs, to gather data about pollution in the skies above the Maldives.

To track how particles of air pollutants help form clouds, the scientists deployed a stack of three AUAVs to fly directly on top of each other. Onboard instruments then monitored conditions below, inside and above the clouds.

It is hoped that the data gleaned from the 18 missions the aircraft flew over the chain of islands will help scientists improve their understanding of how aerosols and other air pollutants are masking the true effects of global warming.

Air pollutants make it easier for drops of water to form in the sky. This causes more clouds to form, and means that more sunlight is reflected back into space.

The process is known as global dimming. Some scientists think that it has caused a drop in global temperatures in particularly polluted regions, which is protecting us from the full impact of global warming.

The skies over the Maldives are blighted with “brown” clouds from industrial activity in nearby India.

Veerabhadran Ramanathan from Scripps said: “Based on [Malvides AUAV Campaign] MAC’s success it is possible that in five years, hundreds of lightweight AUAVs will be documenting how human beings are polluting the planet and hopefully provide an early warning system for potential environmental disasters in the future.”

Jay Fein, program director in the National Science Foundation’s Division of Atmospheric Sciences, agreed: “They will serve as critically important additions to our atmospheric measurement capability in addressing one of the major outstanding issues in climate change science: how does pollution affect cloud microphysical and radiative processes in the context of weather and climate?”

Jess McCabe