EMEA News
Research on Shipping Contrails Points to Tighter Targets in GHG Reduction
Research into a more obscure form of ship pollution has discovered something previously not know.
That the effect of aerosols in shipping emissions on cloud formation, the contrails from shipping's exhaust, changes the water content in clouds -- with a net result to 'cool' global temperature.
Previous studies looking at aerosols from ship funnels used satellite imagery to assess their effect on clouds – some are clearly affected, but many more clouds appeared unaffected, according to the New Scientist magazine.
But Peter Manshausen at the University of Oxford used data to show that clouds that were previously thought to be unaffected were being affected.
With "tracks of clouds [showing] fewer droplets but more liquid water", the overall reflectivity of the clouds is changed slightly. "More importantly, a larger water-to-droplet ratio implies a stronger cooling effect, so the clouds would reflect more radiation back towards the sun," the report said.
Applying the discovery more widely to pollution from other sectors, the overall effect is to reduce the warming factor than currently assumed by climate modelling.
“If the aerosols cause the clouds to be brighter than we thought previously, that means that as we reduce air pollution for health reasons, we stand to expect more global warming from the lack of this cooling that comes from the aerosol cloud interactions,” Manshausen was quoted as saying.
This may mean we have to cut emissions even further, he added.
