To slow global warming, some scientists are considering cooling the planet by creating whiter, brighter artificial clouds to reflect sunlight. Interestingly, busy shipping routes may inadvertently act as field testers. A new study quantifies the effects of ship emissions on subtropical low-level clouds, observes how the period blocks sunlight, and measures its impact on global temperatures.
NASA Earth Observation Satellite Images Show Clouds Sown on Shipping Routes
When cargo ships sail around the world, the burning of fossil fuels eliminates many pollutants, including sulfur particles.
These particles act as “seeds”, and water vapor in the air condenses on these particles to form water droplets that gather into clouds and act as a bright mirror.
The higher the concentration of particulate matter such as sulfates in the air, the more small droplets will be. In addition, the higher the clouds, the greater the effect of reflection.
Although we have known about this phenomenon for many years, a new study from the University of Washington has provided a rare insight into its impact on the climate through years of continuous observation.
Michael Diamond, a doctoral student in atmospheric science at the University of Washington, said they compared simulations of sulfur emissions from non-shipping in climate models and found that the phenomenon had a considerable cooling effect.
Unfortunately, because there are so many natural variabilitys, it’s hard to see the real world the same way. So using satellite data, the scientists looked at cloud dispersion on the Euro-South African route from 2003 to 2015.
After analyzing the nature of the route cloud, measuring the data, and comparing the natural clouds in nearby unpolluted areas, the researchers finally determined the effect of the transmission of pollutants on the airway cloud reflectivity.
NASA Satellite Observations from 2003 to 2015 (from: University of Washington)
“Because of the small differences in routes, we need about 6 years of data to confirm the veracity of this phenomenon,” said study co-author Hannah Director, a doctoral student in the Department of Statistics at the University of Washington. If it can happen globally, it will be enough to affect global temperatures”.
The team expects improved clouds along the route to block 2W/m2 (10.7 sq ft) of additional solar energy near the route. To explore the global impact of this phenomenon, the team also looked at the effects of various forms of industrial pollution on clouds, which are expected to block 1W/m2 of solar energy.
They concluded that without the cooling of these modified clouds, the Earth might have warmed up by 1.5 degrees Celsius (2.7 degrees F) since the late 1880s.
Finally, Michael Diamond says the study doesn’t give an answer to “whether it’s a good idea to increase clouds by sea.”
After all, scientists don’t think transportpollution is a good thing for the global climate, and they need more time to quantify the effects.
Details of the study have been published in the recent issue of the journal AGU Advances.
Originally published as “Cosby Cloud Brightening From Shipping in Sub Low Low Clouds.”