How humans are changing clouds – with Dr Ed Gryspeerdt

Dr Ed Gryspeerdt - Associate Professor in Atmospheric Physics, Dept of Physics, Imperial. Clouds are one of the most striking features of Earth when viewed from space. Covering around two thirds of the Earth at any one time, they have a strong control on the amount of Energy the Earth receives from the sun and hence on the temperature of the Earth. Composed of droplets (or crystals) smaller than the width of a hair but embedded in storm systems hundreds to thousands of kilometres across, simulating clouds remains challenging, even on the world’s largest supercomputers. This makes them one of the largest uncertainties in our understanding of past and future climate change. Observations of clouds are essential to reduce this uncertainty, but measuring the controls on clouds from purely passive observation is difficult. However, the particulate emissions from transport (particularly ships and aircraft) inadvertently change cloud behaviour, giving us a way to ‘experiment’ on clouds ‘in the wild’ and providing some of the best tests we have for clouds in state-of-the-art weather and climate models. In this talk, Dr Gryspeerdt described how clouds work, their impact on the climate and how we can use ‘natural experiments’ to understand how they will change in the future. Edward Gryspeerdt is a Royal Society University Research Fellow and Associate Professor in Atmospheric Physics at Imperial, where he leads a team assessing the human impact on the climate through changes in clouds. This has included using satellites to track shipping pollution, showing how new aircraft technology can reduce the climate impact of flying and identifying the cloudiest place on Earth.