The Cost of Lightning | WIRED

It was the terrible prospect of lightning one day striking the historic windmill that troubled Andrew Farrell. A bolt five times hotter than the surface of the sun instantly turning moisture in one of the mill’s timbers to steam, exploding it. What if a raging fire then engulfed the 160-year-old building? Perhaps most troublingly, he couldn’t shake the thought that this nightmare might be getting more likely with every passing year—because of climate change.

So Farrell of the Broads Authority, a British public body, decided to get a lightning-protection system installed on Mutton’s Mill, a 19th-century windmill that stands on the flat, wide wetland landscape in eastern England known as the Norfolk Broads.

“These mills stick out as perfect conductors into the sky,” says Farrell. Inside Mutton’s Mill is a rare waterwheel, once used to drain the marshes here for agricultural purposes. The mill itself is a protected historical building measuring 23 meters tall, including its sails. Thousands have been spent on restoring it in recent years.

Now, hooked conducting rods on the ends of the mill’s four sail arms are in place, ready to seize an angry lightning bolt and transmit it harmlessly down to rods buried in the nearby marsh. Farrell is confident this could save the historic structure. Though he adds: “You know, if it gets struck, it’ll probably scare the bejesus out of the owl that hangs out up there.”

According to the UK’s Royal Meteorological Society, for every degree of atmospheric warming, the air can hold about 7 percent more moisture. Warmer, wetter air means a greater risk of thunderstorms and, therefore, lightning strikes, the Society adds. Farrell says that, anecdotally, he has already noticed rising electrical storm activity in Norfolk. Scientists remain uncertain over the extent to which lightning might increase in frequency around the world. But organizations are already taking the threat seriously—and quietly moving to protect buildings and critical infrastructure from future strikes.

Based on information found in online documents, among the bodies currently weighing up the risks is Scottish Water, which has contemplated lightning strikes at biogas sites potentially becoming more likely—such incidents could harm workers or members of the public. The International Civil Aviation Organization has, for its part, considered the possibility of more frequent lightning causing disruption to flight schedules, damaging aircraft, or incapacitating radar towers. Network Rail in the UK also discusses the threat to signaling and electrical equipment on the railways in a presentation document.

And in a 2021 report, National Grid Electricity Transmission, the company that maintains the high-voltage power network in England and Wales, said it had already gathered “evidence that lightning strikes around our assets are increasing in some areas.” While the system is largely resilient at present, the report adds, “consideration of the impact of increased lightning will be required in the future.”

The US Department of Defense also cares about lightning, says Caroline Baxter, a senior adviser at the Council on Strategic Risks. “Something that has gone underappreciated is the risk that military installations face from the effects of climate change—including things like lightning,” she says, noting that some states particularly prone to lightning, such as Louisiana and Georgia, also happen to be home to major military bases.