New research has shown that there was less lightning activity during the Spring of 2020—the height of lockdowns across the world. The drop is attributed to decreased air pollution during that period.
A Pleasant Lockdown Outcome
Researchers from the Massachusetts Institute of Technology say as the majority of people sheltered in place, there was a drastic reduction in pollution because less fossil fuel was being used. Earle Williams, a physical meteorologist at MIT, said:
Automobile traffic has a big impact on surface aerosol production. People stopped flying, people stopped using public transportation, people stopped driving. So, there was less pollution.
The burning of fossil fuel burning leads to the production of aerosols that play a role in thunderstorm build-up by acting as tiny particles around which moisture can condense. The more aerosols there are, the smaller the droplets they produce, which then fall as rain.
The size and number of these droplets cause them to freeze into ice crystals, which in turn can lead to the production of static electricity that powers lightning bolts.
According to the researchers, this effect was highly pronounced in March, April and May 2020—the height of Covid-19 lockdown.
8% Drop In Lightning Activity
Satellite images from that period pointed to a significant reduction in the amount of aerosol pollution in places like China, Southeast Asia, Europe and sub-Saharan Africa. The Maritime Continent of Indonesia, the Philippines and neighbouring island nations also recorded cleaner air during the first lockdown.
Comparing the years 2018 to 2021, season to season, the researchers found a significant drop in lightning and aerosols in most places during the lockdown. They also concluded that there was an 8% drop in lightning activity worldwide.
Presenting their findings at the American Geophysical Union meeting in New Orleans last month, Williams said:
There is every indication you will have more lightning in a warmer world. It depends on whether the future is cleaner or dirtier.