In India, lightning strikes have led to hundreds of deaths over the past two months. The country is currently in the middle of its monsoon season, which typically lasts from June to September. “This year, the number of lightning incidents and lightning deaths is more frequent over Bihar and eastern Uttar Pradesh [states in Northern India] because the region is seeing intense monsoon rain quite early,” said Sunitha Devi, a member of India’s Ministry of Earth Sciences’ thunderstorm working group.
Climate change significantly increases the frequency of lightning strikes and rainfall. Global warming has contributed to a warmer atmosphere. Higher temperatures also provide more convective available potential energy (CAPE) which gives storms the fuel for rain, hail, wind, and lightning. CAPE is a measure of how much energy an air parcel would gain by being raised to a specific height in the atmosphere. This means that the more potential energy an air parcel possesses, the higher the chances are that the parcel can produce convective weather systems like thunderstorms and tornadoes.
Climate change also affects lightning strikes. Currently, there are around 25 million lightning strikes per year. A study conducted by the American Association for The Advancement of Science in 2014 concluded that a rise in one degree Celsius in temperature contributes to a 12 percent rise in lightning strike frequency. David Romps, an atmospheric scientist at the University of California, Berkeley came to this conclusion after creating a model based on CAPE and precipitation rates to model the frequency of lightning strikes across the continental United States. They deduced that a warmer atmosphere holds more moisture, which is one of the key ingredients for triggering a lightning strike.
Lightning is not just an effect of climate change, it is also a cause. Lightning produces a gas called ozone. Normally, ozone acts as a protective layer in the stratosphere, the second layer of Earth’s atmosphere. The stratospheric ozone layer filters out harmful UV radiation, but when storms are strong enough, lightning can bring ozone down into the troposphere, the innermost layer of the atmosphere, where it will act as a greenhouse gas instead. According to a study conducted by NASA and the Texas Air Research Center, the amount of ozone that lightning creates is greater than those created by human activities in the troposphere. Lightning creates ozone, which causes global temperature levels to rise, which causes more lightning.
The increase in storms and lightning strikes drastically affect people. Lightning is one of the deadliest natural disasters. According to National Geographic, annually about 2,000 people are killed worldwide by lightning. However, even though lightning is a random event, it and increased storms disproportionately affect rural areas. A report conducted by Ron Holle, a research meteorologist, found that most lightning deaths in Asian countries were farmers that died working in rice paddy fields. Devi explained, “Paddy field water attracts electricity and farmers on the field [can] act as conductors of electricity from the thunderstorm.”
Sanjay Srivastava, a chair of the Climate Resilient Observing-Systems Promotion Council (CROPC) and Covener of the Lightning Resilient India Campaign has proposed many solutions to try to lower the rate of lightning fatalities in India. Although the state government in India sends out warnings through text messages and television channels, many farmers in rural regions do not have access to these warnings. Srivastava believes that more groundwork is necessary. “The farmers did not get the warning sent across, and the only way they can be protected is by tackling things at the [village council] level and educating farmers,” Srivastava said.
Other cheap and accessible means of prevention are lightning conductors. In rural regions of India, a 30-foot bamboo pole with metal wire is buried five feet deep, filled with water, and a bicycle rim on top. The lightning conductor provides a safe space of 2–3 acres. More expensive methods like lightning sensors are also being used to provide effective early warning. In the Indian state of Odisha, deaths due to lightning strikes fell by 31 percent due to the State Disaster Management Authority implementing six lightning sensors. A lightning sensor constantly monitors atmospheric electrical activity and then calculates the potential for lightning strikes in a given area. Using this data, the government sends out warning messages to at-risk residents.
While there has been much work done to prevent lightning-related casualties, people all over the world still get caught in storms with no idea what to do. A majority of lightning-related deaths take place because people seek shelter under trees. John Jensenius, a lightning safety specialist at the National Oceanic and Atmospheric Administration, relays some safety tips.
“Taking shelter in a car or enclosed building is always your best option,” Jensenius said. If there is no shelter around, he encourages people to avoid trees, ravines, concrete and wet or metal objects, as they are conductors of electricity. The Center for Disease Control advises people caught in a storm to crouch low, with as little of one’s body touching the ground as possible because lightning causes electric currents along the top of the ground that can be deadly over 100 feet away.
While the odds of being struck by lightning are low, the influence of climate change on lightning strike frequency and thunderstorms are troubling. It is important to think about the indirect effects of climate change. Rising temperatures are not the only concern, but also increased lightning fatalities. The positive feedback loop of global warming and lightning strikes may have serious impacts on the future.