‘Hot lightning’ that sparks wildfires can surge due to global heating, study warns

A warming planet could lead to more “hot lightning” strikes in many parts of the world, a form of lightning bolt that is much more likely to spark wildfires.

Researchers, including those from The Institute of Astrophysics of Andalusia in Spain, said lightning-ignited wildfires produce large emissions of carbon, nitrogen oxides and other gases, playing a key role in the climate crisis.

Previous studies have already found that the global occurrence of lightning flashes may increase due to global heating, especially over land and in the oceanic region of southeastern Asia.

In the study, published recently in the journal Nature Communications, they assessed the types of lightning strikes that lead to wildfires and the likelihood of their increase with global heating.

Overall, scientists analysed 5,858 selected lightning-ignited fires based on satellite images of US wildfires between 1992 and 2018.

Wildfires are more likely to start due to Long-Continuing-Current (LCC) lightning flashes that last much longer than average to nearly a third of a second.

These lightning strikes that flash with continuing current are sometimes referred to as “hot lightning” because of the heat they generate, according to the US National Oceanic and Atmospheric Administration.

In the latest analysis, researchers found a 41 per cent global increase in LCC lightning strikes.

The frequency of such lightning flashes could increase from about three strikes per second to four per second across the world.

All types of lightning strikes may increase by about 30 per cent by the end of the century, researchers pointed out.

“Increases are largest in South America, the western coast of North America, Central America, Australia, Southern and Eastern Asia, and Europe,” they wrote in the study.

However, only regional variations were found in the northern polar forests, they explained, adding that these are regions where fire risk can affect soil carbon release and contribute to more global warming.

Researchers have called for future studies to identify the weather behind lightning-ignited wildfires in some regions of the world and to assess conditions where such wildfires are frequent, but there are not enough fire reports.

The new findings, they said, also call for the need to include LCC lightnings in future climate modeling.

“These results show that lightning schemes including LCC lightning are needed to project the occurrence of lightning-ignited wildfires under climate change,” scientists added.