Satellite images have shown how quickly clouds react to harmful substances emitted by ships. This allows researchers to more accurately model the climate in the near future.
In order to create accurate climate models, it is important to know how the pollutants released by burning fossil fuels change clouds. In particular, they can change the reflectivity of clouds.
Higher reflective clouds will reduce the energy reaching the Earth’s surface and therefore reduce global warming. Therefore, it is important to get an accurate picture of how clouds react to human pollutants.
Knowing the rate at which clouds change in response to pollutants is essential to understanding their impact on climate. Researchers from Imperial College London, Leipzig University and University College London decided to use harmful substances from ships as a kind of stopwatch and measure the speed of this process.
The substances that form the ships are clearly visible inside the cloud formations – the researchers call them “ship tracks”. In the open ocean, clouds are unlikely to be influenced by factors other than aerosols, making ship tracks ideal candidates for such an experiment.
The team examined satellite images of ship tracks and used wind information and logs to determine how long ago each ship passed certain points. They could then relate the cloud state to changes caused by the ship’s emissions.