Lightning is a serious hazard in many parts of Africa, which is one of the main global hotspots of lightning activity. As well as the risk to people and infrastructure, lightning  is a natural cause of wildfires. Lightning also affects key features of atmospheric chemistry such as ozone production in the upper troposphere. As with many weather phenomena, lightning is likely to respond to climate change, with past studies generally suggesting that there will be an increase in lightning.

Lightning over Kenya (Source: Flickr)

Lightning depends on ascending air in thunderstorms, and the collision of cloud ice particles which charge the thundercloud, but climate models normally have too coarse a resolution to reliably capture these processes.

A new study by HyCRISTAL researchers shows that using a model that is much higher resolution than usual allows us to explicitly simulate the deep convection associated with thunderstorms, as well as provide more detailed representation of the distribution of cloud ice particles. The results show that in drier regions, as well as the much wetter Congo, there is relatively more lightning per kilogram of surface rainfall than there is in other parts of the continent. Lightning does increase across the continent under climate change, but by a relatively small amount. This is despite the number of days with lightning decreasing as the lower atmosphere becomes more stable. On days with lightning, there are more lightning flashes because there is an increase in cloud ice and intensity of convection. This study gives much more detailed information about African lightning than previous work. We recommend that future research should look at these results across other climate models run at high resolution, as these results are for a single model for a single possible global realisation of climate change.

Download the paper: African Lightning and its Relation to Rainfall and Climate Change in a Convection‐Permitting Model.