Blog

Thunderstorms cause floods, fires, and blackouts, but did you know they also indirectly pollute our air? Lightning ignites complex chemical reactions that result in the formation of ozone, a chemical that causes a range of breathing issues and harms our agricultural industry. And now, as our air gets warmer due to climate change, we are experiencing stronger and more frequent thunderstorms, prompting scientists to examine the link between thunderstorms and air quality more closely. Soon, scientists will have a new space-based tool that can help us better understand what connects climate change, lightning, and air quality: Tropospheric Emissions: Monitoring of Pollution, or TEMPO.

It may seem odd that there’s more to learn about thunderstorms, a weather event so ubiquitous that it’s appeared in mythological cannon dating back to ancient times. Plus, it’s difficult to look at such a common weather event and imagine how it might relate to the relatively modern phenomenon of present-day climate change. But while thunderstorms and the impact they have on our climate aren’t new, their frequency and intensity are. This change has caused scientists to add thunderstorms to the growing list of natural events that have not only been worsened by climate change but are also part of what makes climate change such a threat to our planet.

Of all the events associated with thunderstorms, lightning contributes most to the generation of ground-level ozone. Lightning shoots through the air at the speed of light and carries with it a temperature of 50,000° F, or five times the temperature on the surface of this sun. Lightning causes the air around it to rapidly heat up and cool down, leading chemicals in the air to react in ways they would not under normal conditions. First, the nitrogen in our air, which normally comes pair-bonded, breaks into individual nitrogen atoms. Then, the nitrogen atoms react with oxygen, resulting in the production of nitrogen oxides, which are some of the main ingredients for creating ground-level ozone. If you’ve read our previous blog on the good and bad effects of ozone, you know why this is bad news.

Normally, lighting does not create enough ozone to cause a problem relative to major emitters such as factories and automobiles, but climate change gives scientists a new reason to evaluate the impact of lighting on our atmosphere. Warmer air can hold more moisture, a key element that drives storms to form. As a result, as climate change causes global temperatures to rise, so too will it cause a rise in storms. In fact, in 2014, researchers predicted that by the end of this century, the number of lightning strikes per year across the contiguous United States will increase by half. These researchers predicted that with every degree Celsius that the average temperature increases, the number of lightning strikes will increase by 12 percent. In the end, this means climate change will likely increase the total amount of ozone produced by thunderstorms.

TEMPO will sit over North America and sweep the continent once per hour to monitor major air pollutants in the atmosphere, and the research team will be able to focus the instrument on specific events such as thunderstorms to study the amount of ozone they produce. Researchers at the Center for Astrophysics, NASA, and partners such as the EPA and NOAA will be able to analyze how climate change is causing the release of more ozone as thunderstorms become more common. Interestingly, it’s also possible that data collected from space could reveal good news about lighting and climate change.

Some researchers believe that more lighting might benefit the atmosphere, and the Center for Astrophysics | Harvard and Smithsonian (CfA) is developing another space-based instrument to help answer that question. In 2021, researchers discovered that lighting produces large amounts of highly reactive molecules that break down greenhouse gasses like carbon dioxide and methane, but it’s unclear if this effect is strong enough to counteract the ozone created by lightning. Using MethaneSAT, which is launching into space in early 2024, the CfA will add methane to the list of atmospheric pollutants it can measure from space. With TEMPO and MethaneSAT, the CfA will be able to monitor the same region to study the overall impact of a thunderstorm. In the long term, these two instruments could help scientists determine whether an increase in lighting shields us from some of the effects of climate change or if it exacerbates the problem.

The next time you see lighting flashing in the sky, think about the immense heat it is releasing and the massive impact it’s having on the air around it. Lighting is one of the most powerful natural phenomena known to humanity, creating the hottest temperatures on Earth – so hot that it produces a fourth state of matter beyond gas, called plasma, wherein atoms are so hot that they split into charged particles. Thunderstorms can produce up to 1.3 billion volts of electricity, which is enough electricity to power over 10 million power outlets across the US. Lightning bolts are the stuff of legend and a spectacle to watch. People have observed them, studied them, and written stories about them for millennia, and now, using the latest technology in space, we can study their effects on atmospheric ozone like never before.