Here’s how lightning may help clean the air

Airplane observations show that storm clouds can generate huge quantities of air-cleansing chemicals known as oxidants.

Here’s how lightning may help clean the air

Lightning may play an important role in clearing the air of pollutants.

A storm-chasing airplane has shown that lightning can forge large amounts of oxidants. These chemicals cleanse the atmosphere by reacting with pollutants such as methane. Those reactions form molecules that dissolve in water or stick to surfaces. The molecules can then rain out of the air or stick to objects on the ground.

Supercell: It’s the king of thunderstorms

Researchers knew lightning could produce oxidants indirectly. The bolts generate nitric oxide. That chemical can react with other molecules in the air to make some oxidants. But no one had seen lightning directly create lots of oxidants.

A NASA jet got the first glimpse of this in 2012. The jet flew through storm clouds over Colorado, Oklahoma and Texas in both May and June. Instruments on board measured two oxidants in the clouds. One was hydroxyl radical, or OH. The other was a related oxidant. It’s called the hydroperoxyl (Hy-droh-pur-OX-ul) radical, or HO2. The airplane measured the combined concentration of both in the air.

Explainer: Weather and weather prediction

Lightning and other electrified parts of the clouds sparked the creation of OH and HO2. Levels of these molecules rose to thousands of parts per trillion. That may not sound like much. But the most OH seen in the atmosphere before was only a few parts per trillion. The most HOever seen in the air was about 150 parts per trillion. Researchers reported the observations online April 29 in Science.

“We didn’t expect to see any of this,” says William Brune. He’s an atmospheric scientist. He works at Pennsylvania State University in University Park. “It was just so extreme.” But lab tests helped confirm that what his team saw in clouds was real. Those experiments showed electricity really could generate lots of OH and HO2.

Scientists Say: Climate

Brune and his team calculated how much of the atmospheric oxidants that lightning could produce around the world. They did this using their storm-cloud observations. The team also accounted for frequency of lightning storms. On average, some 1,800 such storms are raging around the globe at any point in time. That led to a ballpark estimate. Lightning could account for 2 to 16 percent of atmospheric OH. Observing more storms could lead to a more precise estimate.

Knowing how storms affect the atmosphere may become even more important as climate change sparks more lightning.

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Analyze This: Invasive species cost the world billions each year

A new study estimates that invasive species have cost the world more than $1 trillion since 1970. That’s almost certainly an underestimate.

Analyze This: Invasive species cost the world billions each year

Invasive species can wreak havoc on ecosystems. These organisms settle into and cause harm in places where they aren’t native. For example, mosquitoes spread diseases. Cats kill birds and some mammals. Many insects chew up crops or kill trees. Such damage can be very costly. So is managing the mayhem they cause. New research suggests that just between from 1970 and 2017, invasive species cost the world at least $1.28 trillion.

“By estimating the global cost, we hoped to raise awareness of the issue,” Boris Leroy . A biogeographer, Leroy studies how life, such as plants and animals, spread across regions. He works at the French National Museum of Natural History in Paris. Researchers have studied invasive species for decades, he says. But many people remain unaware of the problems these eco-bullies cause.

Leroy and his team set out to tally that cost. They scoured research papers for estimated costs of specific invasions. They came up with 1,319 studies to analyze. To find long-term trends in costs of invasions, the researchers used a computer model. It let them account for currencies used in different countries and how the value of money changed over time.

The new study examined costs of dealing with damage plus the cost of managing the species. Damage control cost about $892 billion. That’s 13 times more than the $66 billion spent on such efforts as ousting invaders or controlling their spread. The total yearly cost of invasive creatures doubled roughly every six years between 1970 and 2017. In 2017, that annual bill reached $162.7 billion, the team reports March 31 in Nature.

Scientists Say: Invasive species

Many invaders hitch a ride to new places via cargo ships and planes. So inspecting cargo or monitoring for new pests could help lower the cost of invasions, says ecologist Helen Roy. “It’s much cheaper than waiting for the species to establish and spread widely before responding,” she says. Roy works at the U.K. Centre for Ecology and Hydrology in Wallingford, England. She was not involved with the study.

The new results are likely an underestimate. That’s because research on invasive species doesn’t capture the whole problem. For instance, more reports focus on North America and Europe than on what’s happening in South America or Africa. And pests that harm crops, such as insects, get more attention than do invasive plants. However, Roy notes, the study does show that invasive species are “a massive problem that’s getting worse.”

Data Dive:

  1. What was the cost of the most expensive invasive species?
  1. Look at the different colors making up that first bar. Roughly how much of the total cost is due to damage? How much of the cost is due to management?
  1. Which three invasive species have cost the most damage? What is the total damage cost of these three creatures?
  1. Which invasive species has the highest management cost?
  1. How many of the 10 costliest invaders are insects? How many are mammals? How many are reptiles?
  1. Choose one of the species. What kinds of damage can this creature cause? How might this animal affect other wildlife? How might it affect people? How might this animal affect crops or buildings?
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