A team of scientists from multiple institutions including the Andalusian Institute for Astrophysics has presented years of evidence about a warming planet and its impact on lightning activity and forest fires. The research highlights a clear link between rising temperatures and more frequent fires, a finding reinforced by data from the Iberian Peninsula and beyond. The study appears in Nature Communications.
Global analyses indicate that lightning strikes could rise by about 40 percent by the end of the century, corresponding to roughly a 10 percent increase in frequency per degree of warming. The research shows that changing weather patterns will raise the risk of fires sparked by lightning around the world.
The investigation began with satellite imagery of wildfires in the United States from 1992 to 2018. By comparing lightning types with the fires that followed, the team found that fires initiated by lightning are common. In the data they reviewed, about nine in ten fires started this way.
The scientists then tracked lightning activity over time. Computer simulations showed a higher occurrence of discharges as the atmosphere warmed. Climate models project a rise from roughly three to four lightning bolts per second worldwide.
The study also identified regions most at risk for increased lightning as temperatures climb. South America, Southeast Asia, Australia and Africa are highlighted as areas with elevated risk. North America is shown to experience the greatest relative rise in lightning-driven fires, while polar regions are expected to see fewer fires due to increased precipitation turning into surface moisture from warming.
More lightning and more fire in the Spanish Levante
On the Iberian Peninsula, maps from the study indicate heightened lightning activity along Spain’s Mediterranean slope, which translates to a higher forest fire risk in that region.
According to the study’s lead author, Francisco J. Pérez-Invernón of the IAA, stronger air currents in storms along the Mediterranean coast will drive more frequent lightning and longer discharges, increasing fire risk in that sector.
Higher temperatures and drier storms raise the likelihood that lightning will start and spread fires in this area. Dry storms occur when hot air near the surface keeps rain from reaching the ground, boosting fire ignition chances from lightning. The team notes that results in other parts of the peninsula remain inconclusive.
A notable finding is the potential variation in the frequency of direct current lightning, a form of very long discharges that deliver extra energy to vegetation and raise the chance of ignition. Direct current lightning accounts for roughly 10 percent of all lightning events.
A new stationary satellite, Meteosat Third Generation, launched by Europe in late 2022, is set to generate data soon. Its onboard optical instrument can observe, for the first time, continuous lightning events across Europe and Africa.
Perez-Invernón notes that the future data and regional models will enhance predictions of lightning related fire risk in the Iberian Peninsula.
Reference work: https://www.nature.com/articles/s41467-023-36500-5
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