This scientist, who studies the air, travels from New York City to the Arctic to discover what’s in the atmosphere.
New York has a challenge with counting greenhouse gases. They try to keep track of where things like pollution come from, like making energy, driving cars, and handling trash. But sometimes, what they write down doesn’t match what’s really in the air. It’s like a puzzle, especially with the amount of methane (a type of gas) over New York City, which is more than they thought it would be.
Róisín Commane is like a detective on a mission to solve a mystery. She’s not solving crimes, but she’s exploring the city like an accountant and a sleuth combined. This scientist from Columbia University checks everywhere in the city, from the ground to the tops of buildings, to find sources of greenhouse gases that might not be known or recorded correctly. By doing this, she helps us better understand the gases people create in the city.
There are two main ways to figure out how much pollution is in the air. The first way is called ‘bottom-up.’ It adds up all the pollution from different things like cars or factories using average numbers for each type of pollution. The second way is called ‘top-down.’ It looks at the overall pollution in an area using measurements taken directly from sensors on towers or planes.
The tricky part is making sure both ways agree,” says Commane. “We can adjust the models to match how the air really is today.
This job is really important. Cities make up about 70 percent of the world’s carbon dioxide emissions. In the United States, among all the cities, New York City is the biggest producer of greenhouse gases from things people do.
Keeping track of greenhouse gases in a better way can help New York achieve its goal of not adding more carbon by 2050. It will also help them see if the things they’re doing to reduce pollution are working,” says Commane. “We all want to do good things, but it’s even better if we can prove we’re actually making less pollution.
And what they discover in New York City can help other places too, especially those with similar ways of getting natural gas.
Emissions estimates don’t match reality.
Commane thinks of atmospheric modeling like figuring out a tricky puzzle. ‘I’ve always liked playing with numbers,’ she says.
She went to University College Dublin in Ireland and studied chemistry and mathematical physics. Then, she got a special degree (called a Ph.D.) in atmospheric chemistry from the University of Leeds in England. During that time, she learned how to create tools that can measure the gases in the air, using cool things like laser systems.
An air scientist named Steven Wofsy, who helped Róisín Commane when she was doing research at Harvard University, admires how she can ‘think about problems in a big picture way.’ He says she’s very creative, especially in the work she did about carbon in the Arctic. Many scientists usually just look at the summer when plants take in a lot of carbon from the air. But Commane didn’t stop there. She continued her experiment into the winter when the ground freezes, and tiny living things in the soil that usually make and release carbon go to sleep.
Commane discovered that in warmer years, if the freezing in the Arctic takes longer, the soil might let out enough carbon to cancel out what the plants took in during the summer. This could make the Arctic not a helper but actually someone who adds more carbon dioxide to the air.
Thinking about the Arctic makes me a bit sad,” says Commane, “because it’s warming up really fast there. The Arctic is having a tough time because of what we’re making down here on Earth.”
In 2018, Commane started her own lab at Columbia University, which gave her the chance to work on the problem right from where the emissions come. New York City is a big part of the issue, being the top source of greenhouse gases in the United States and the third-highest in the whole world.
She began by studying the gases that make the air not so good, like carbon dioxide and methane, in the city. She worked together with other scientists from different universities in New York, like the City University, Stony Brook University, and the University of Rochester. They made a bunch of monitors to check the air in the city and the state.
She also saw how much green stuff there is in the city. New York has around 7 million trees, but when people count how much carbon is around, they usually forget to include the plants. Commane noticed this.
Commane wondered if the trees in the city could explain why the air didn’t have as much bad carbon as the models thought. She and her friend Dandan Wei, who helps in her lab, used the newest maps that show where there are lots of plants in their model. They found out that the trees in the city take in a surprising amount of carbon dioxide, especially in the afternoon. On a summer day, they soak up about 40 percent of the bad carbon that comes from the city.
So, the trees are really important,” says Commane. “The models need to remember them. Otherwise, when people try to figure out how much bad carbon there is in the air from what people do, they might miss the part that the trees are holding onto for a little while.
Eyes on methane.
When it comes to methane, there’s a lot more in the air above the city than what the models said there should be – at least three times more. But nobody knows why there’s so much extra.
To solve this mystery, Commane checks how much methane there is compared to other gases like carbon dioxide, carbon monoxide, and ethane. When her sensors find big clouds of gas, she uses a special trick called ‘source attribution’ to figure out where the clouds came from. The speed of the wind and how strong the cloud is help her know which way it came from and how far away it is.
Then, it’s time to either drive around in a car or walk to find out exactly where the extra gas is coming from using special sensors,” says Commane.
So far, her team found out that a lot of the extra methane is coming from chimneys and rooftops. This happens when natural gas, used for heating buildings, doesn’t burn completely. They also discovered higher levels of methane near certain things in old garbage dumps that are now closed. The good news is that by making some changes, like fixing leaks, they can stop the extra gas from getting out. The biggest amounts of methane came from older places that treat wastewater, but the good news is that newer, improved places hardly let out any methane at all.
What Dr. Commane is doing is really important,” says Ellen Burkhard, who helps make decisions at the New York State Energy Research and Development Authority, the group that supports Commane’s work.
By checking things out on the ground in a smart way, and doing it many times, we can figure out where the extra gas comes from and how it might change over time,” Burkhard explains. “It’s just like when people say: You can’t solve a problem if you don’t know what the problem is.”
While Commane works on different projects, she loves teaming up with the energy research agency because they focus on finding solutions. It helps her stay realistic but also hopeful in the battle against climate change. “If we didn’t have a plan to try and make things better, it would feel like we can’t do anything,” she says. “But here, I can actually do something. And that makes a big difference, I think.”
Róisín Commane
Principal Investigator
I study how things on the ground and in the air interact and change what’s in the air.
I’m a scientist who studies the air and the gases that stay in the air for a long time. I’m curious about how different places, like the Arctic, regular areas, and big cities, affect what’s in the air. Lately, I’ve been setting up a special network of devices to measure gases like CO2 and methane in and around New York City.
Before this, I flew in a NASA airplane called the DC-8 to measure gases in the faraway sky as part of the ATom project. I also spent time understanding carbon dioxide and methane in the Arctic with projects called CARVE and ABoVE. We wrote articles about CARVE in a science journal called PNAS in 2017.
A while back, I created a special tool that uses lasers to measure a gas called carbonyl sulfide (OCS). I used it in a place called Harvard Forest in Massachusetts to learn about how this gas moves. I worked with other scientists who study nature to figure out more about it. We wrote about OCS in a science journal called PNAS in 2015.
Professional Experience.
July 2023 – Present: Associate Professor, Department of Earth & Environmental Science (DEES), Lamont-Doherty Earth Observatory, Columbia University in New York City, New York
July 2018 – June 2023: Assistant Professor, Department of Earth & Environmental Science (DEES), Lamont-Doherty Earth Observatory, Columbia University in New York City, New York
September 2012 – July 2018: Research Associate, Harvard University, Cambridge, Massachusetts
September 2009 – August 2012: Postdoctoral Fellow, Harvard University, Cambridge, Massachusetts
Education.
2003: Bachelor of Science (Joint Honors in Chemistry and Mathematical Physics), University College Dublin, Ireland
2005: Master of Research in Biomolecular Science, Department of Chemistry, Imperial College, London, UK
2009: Doctor of Philosophy in Atmospheric Chemistry, School of Chemistry, University of Leeds, UK
