First global map of cargo ship pollution reveals effects of fuel regulations

Thu, 04 Aug 2022 05:11:47 GMT
Space Daily

Baltimore MD (SPX) Aug 03, 2022 A new study in Science Advances led by UMBC's Tianle Yuan used...

A new study in Science Advances led by UMBC's Tianle Yuan used satellite data from 2003 - 2020 to determine the effect of fuel regulations on pollution from cargo ships.

This huge advance allowed them to generate a comprehensive, global map of ship tracks over an extended period for the first time.

Disappearing act Even before pollution-limiting regulations were put into place, Yuan and his colleagues found that ship tracks didn't occur everywhere ships were traveling.

They also found that after Europe, the U.S., and Canada instated Emission Control Areas along their coastlines in 2015, ship tracks nearly disappeared in those regions, demonstrating the efficacy of such regulations for reducing pollution in port cities.

In 2020 an international agreement set a much more restrictive standard for shipping fuel across the entirety of global oceans, rather than only near coastlines.

In clouds with even mild background pollution, the presumed ship tracks blended right in.

"Ship pollution alone can create a substantial cooling effect," Yuan says, "Because the atmosphere over the ocean is so clean." There is a physical limit to how small cloud droplets can get, so at a certain point, adding more pollution doesn't increase the clouds' cooling effect.

Ocean pollution is also an outsize driver of the cooling effect of aerosols, because low clouds, which are most conducive to creating ship tracks, are more common over water than on land.

"We can take advantage of the millions of ship track samples we have now to start to get hold of the overall aerosol-cloud interaction problem," Yuan says, "Because ship tracks can be used as mini-labs."

Research Report:Global reduction in ship-tracks from sulfur regulations for shipping fuel.