• Follow Us On Our Preferred Social Media Platform:

New analysis of shipping emissions reveals air pollution has a larger effect on climate than previously thought

11 Oct 2022

A recently published study ‘Invisible ship tracks show large cloud sensitivity to aerosol’ has found air pollution from vessels having a larger effect on climate than previously thought, according to the University of Oxford on Thursday (6 October).

The study used a global database of ship routes containing the locations of almost all ships at a given time: more than two million ship paths over six years.

The research team analysed data on ship emissions as a model system for quantifying the climatic effect of human aerosol emissions in general.

Sometimes, when a ship passes underneath a cloud, its aerosol emissions brighten the cloud in a long line, similar to a contrail.

These so-called ship tracks have been studied previously, however the vast majority of ships leave no visible tracks. This was the first study to provide a quantitative measure of the impact of invisible ship tracks on cloud properties, and thus their cooling effect.

Brighter clouds reflect more of the sunlight that strikes them, deflecting it from the earth’s surface. However, it is currently unclear how large this cooling effect is, particularly if the cloud brightness change cannot be seen in satellite images.

Key findings of the study:

  • Invisible shipping tracks had a clear impact on the properties of clouds they polluted.
  • Surprisingly, the specific effects were different to those of visible shipping tracks.
  • Invisible ship tracks showed a smaller increase (roughly 50% less) in the number of droplets in the clouds, but the amount of water increased more, compared to the effect of visible tracks. This implies that for a given increase in droplets, the increase in water is larger than thought, equating to a greater cooling effect.
  • The same may be true for aerosol emissions more generally – clouds may react more strongly to air pollution than previously thought, getting brighter and having a stronger cooling effect.

Note: The study ‘Invisible ship tracks show large cloud sensitivity to aerosol’, has been published in Nature


Photo credit: ‘Invisible ship tracks show large cloud sensitivity to aerosol’ study
Published: 11 October, 2022

Related News

Featured News

Our Industry Partners

PR Newswire