The future is not forecast: How lightning is affected by climate change
Lightning is a fascinating yet deadly phenomenon that affects countries all over the world. It is easy to forget when residing in countries like the UK, which experiences less thunderstorms than many others, that in the time it takes you to read a sentence around 200 bolts of lightning have struck the ground across the Earth. With around 100 strikes per second, lightning currently hits the ground around eight million times per day, but that number could be set to dramatically increase as global warming accelerates. As reported in the journal Science, we could expect to see a 12% increase in lightning activity for every 1°C of warming, meaning countries like the US could see a 50% increase in the number of strikes by the end of the century.
What can we expect from our weather?
Examining how global warming could impact our weather is not a neglected field of study, but much of the focus has been on hazards such as hurricanes and not the severity of thunderstorms. This often receives less attention because thunderstorms are more common and the damage they cause is highly localised. But it must not be forgotten that lightning is hazardous; it can strike and kill people, trigger potentially devastating wildfires, play a part in destructive floods and in the case of the US can lead to the creation of tornados.
Thunderstorms happen because of convection, when the heating of the Earth’s surface by sunlight and infrared radiation causes water to condense as buoyant air rises. As CO2 increases and the land surface warms, stronger updrafts are more likely to produce lightning. In a climate with double the amount of CO2, we may see fewer lightning storms overall, but 25% stronger storms, with a 5% increase in lightning.
How bad could the damage be?
Lightning damage is also likely to increase because of its role in igniting forest fires, where dry vegetation, also caused by rising temperatures, creates more “fuel” for fires, so even a small climate change may have huge consequences. For example, lightning strikes killed 147 people in just 10 days during the summer in the north Indian state of Bihar, with the unprecedented surge in deaths caused by lightning being blamed on climate change. The last decade has been the hottest in India since records began, with temperatures averaging 0.36°C above normal. The rising temperatures have also been linked to frequent heatwaves followed by delayed but more intense monsoons, with deadly lightning strikes now expected by those who live there.
The distribution of lightning is directly linked to the Earth’s climate, which is driven by solar insolation. The daily and seasonal heating of the continental landmasses results in large temperature fluctuations, which influences atmospheric stability and the development of thunderstorms. Lightning activity is positively correlated with surface temperatures over short periods of time, and due to projections of a warmer climate in the future, one of the key questions is what the impact of impending global warming on lightning, thunderstorms, and other severe weather will be.
The future is not forecast
While the impact climate change will have on our weather still remains uncertain, researchers agree that by implementing simple measures like lightning detection systems and installing grounding systems in buildings could go a long way in avoiding deaths and injuries. Thunderstorm patterns can’t be changed, but the protection is out there, with lightning detection systems acting as the only reliable and consistent way of issuing a lightning warning. Around 90% of thunderstorms are already producing lightning by the time they are within 12 miles (20 km), making a system an invaluable investment for a future of weather uncertainty.