How Do You Know a Cargo Ship Is Polluting? It Makes Clouds

Satellite imagery of the world's oceans can give you a glimpse of long, thin clouds. Off the West Coast of the U.S., the slashes could create huge hash marks. There is a ship track.

The cargo ships trace their routes for satellites to see. That is because pollutants rise into low-level clouds and plump them up by acting as nuclei that attract water vapor, which in turn increases the visibility of the clouds. Since brighter clouds bounce more of the sun's energy back into space, these pollution-derived tracks actually have a cooling effect on the Climate.

There is a lot of shipping along the coast of California and ideal atmospheric conditions for the tracks to form. At one point it used to be. The amount of sulfur ships are allowed to emit was limited by theIMO in 2020. Air quality around busy ports improved when shipping companies switched to low sulfur fuel. In doing so, they reduced the number of ship tracks, which means less bright clouds and more warming.

The researchers described how they used a new machine-learning technique to quantify the clouds better than before, showing how the sulfur regulation cut the amount of ship tracks over major shipping lanes in half. It has had a warming effect on those regions.

The global ship-track numbers have been reduced to the lowest point on record because of a regulation put forward in 2020. Reduced economic activity may have had a small effect on the situation. Even though cargo traffic has begun to pick up, ship-track activity is still low. WeTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkia The effect isn't global.

Emission control areas, or ECAs, which established local versions of the standards set by the 2020 global rule, have already been removed in Europe and North America. The number of tracks within the ECAs decreased to the point of almost disappearing. There was an increase because the shipping routes had changed.

Satellite imagery showed ships doing something that wasn't obvious. Outside of control zones the vessels burned regular old fuel. The operators could switch to low-sulfur fuel once inside an ECA. The normal component of a fossil fuel is sulfur. Because low-sulfur fuel is more expensive, it is more cost effective for ship operators to burn the old stuff outside of ECAs.