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Climate change has led to an increase in the frequency of lightning strikes around the world, a new study has found. This can lead to a higher risk of lightning-induced wildfires in the future.
Total lightning incidences have gone up 43 per cent globally, along with a 41 per cent increase in long-continuing current (LCC) lightning, according to a study published in journal Nature Communications, February 10, 2023.
Lightning incidents on land have gone up by almost half — a 47 per cent increase in LCC lightning over land was observed.
The largest increase in LCC lightning was in South America, the western coast of North America, Central America, Australia, Southern and Eastern Asia and Europe.
A decreased risk of lightning-caused wildfires in the polar regions was predicted in the 2090s, except in some small areas in Scandinavia, Alaska and Siberia, where the risk could be elevated due to an increase in LCC lightning.
The researchers estimated a large increase in lightning-caused wildfires along the Mediterranean basin and on North America’s western and central coasts in the 2090s.
The likelihood of ignition by LCC lightning is greater than ignition by lightning without continuing currents, said Francisco J. Pérez-Invernón from Instituto de Astrofísica de Andalucía, Spain and the lead author of the study.
The susceptibility of lightning-caused wildfires to climate change could vary based on changes in lightning frequency and meteorological factors that impact fuel availability and fire spread conditions.
Variations would also influence the future patterns of lightning-ignited fires in the duration of continuing currents in lightning strikes, said the study.
The paper called attention to the need to include LCC lightning in climate modelling. Further research is also needed to identify the preferential meteorological conditions of lightning-ignited wildfires in some regions of the world. In Africa, lightning-ignited wildfires are frequent, but there are not enough fire reports.
Implementation of LCC lightning in climate models coupled with vegetation models could also improve the estimates of the area burned by lightning-ignited wildfires under climate change.
The analysis aimed to explore the variation of lightning with continuing currents and meteorological conditions in order to predict future patterns of lightning-caused wildfires.
Under a high greenhouse gas emissions scenario, changes in vegetation and fire weather increase lightning ignition efficiency by 9 per cent in Alaska and 28 per cent in the Northwest Territories of Canada per degree Celsius warming by the end-of-century, said a 2022 study published in journal Environmental Research Letters.
“The increases in lightning ignition efficiency, together with a projected doubling of lightning strikes, result in a 39 per cent–65 per cent increase in lightning-caused fire occurrence per 1°C warming,” said the study by Thomas D Hessilt.
Climate change worsens wildfires by increasing drought, high air temperatures, low relative humidity, lightning, and strong winds resulting in hotter, drier, and longer fire seasons. The findings were reported by a United Nations Environment Programme report Spreading like Wildfire: The Rising Threat of Extraordinary Landscape Fire.
At the same time, climate change is made worse by wildfires, mostly by ravaging sensitive and carbon-rich ecosystems like peatlands and rainforests. This turns landscapes into tinderboxes, making it harder to halt rising temperatures.