Shipping tracks, cloud patterns over the ocean. | Photo NASA.
Ships leave a trail of sulfur dioxide in the sky behind them which seeds clouds and causes cooling. At the same time, black soot drops out on the arctic ice, absorbs sunlight and causes warming. So which effect is bigger? Scott Stephenson et al tried to figure out that out and the cooling effect won.
The researchers also factored in global anthropogenic (human-caused) greenhouse gas concentration trajectories, adopted by the International Panel on Climate Change (IPCC), at a level closely aligning with today’s trends, along with global economic output that will drive the transport of goods.
“We attempted to fully integrate the interactions between the various components of the climate system in ways that have not been done before,” Stephenson says.
The main result was that the cooling effect won out over the warming effect in the simulations, to the tune of about one degree Celsius.
Zowie. One real degree of Arctic cooling sounds like rather a lot — even undoing greenhouse gas warming as well as soot based warming.
The cooling effect stops if we clean the smoke stack and remove the [...]
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