The accidental climate scientist who uncovered an unexpected force of global warming

By Katie Hunt, CNN

(CNN) — Scientist Veerabhadran Ramanathan yearned for the American dream while growing up in southern India in the 1960s: specifically, a Chevrolet Impala, a muscle car he learned about from his father, a tire salesman. Ramanathan made it to the United States in his 20s, but he never bought his gas guzzler, largely because his scientific knowledge of global warming quickly eclipsed his income.

Fast-forward to the 1970s and Ramanathan, now a newly minted postdoctoral fellow in planetary sciences, was spending his days working as a visiting researcher at NASA Langley Research Center in Hampton, Virginia, and his evenings on a side project he hid from his supervisors. His solitary nighttime research would end up changing how scientists viewed global warming.

The young scientist had discovered that chlorofluorocarbons, or CFCs, then widely used in the manufacture of refrigerators, air-conditioning units and spray cans, had a significant greenhouse effect. Ramanathan had briefly encountered these industrial chemicals in his first job at a refrigeration company. Like carbon dioxide, CFCs trapped heat in the atmosphere. In fact, Ramanathan’s calculations suggested, they were more potent: One molecule of a CFC could have the same warming effect as up to 10,000 molecules of carbon dioxide. For three months, he repeated the calculations looking for an alternative explanation. He found none.

“I was just a postdoc immigrant from India. I didn’t know if I should tell NASA about this or not. I just sent the paper off,” Ramanathan recalled.

The journal Science published the findings, and his work made the front page of The New York Times in 1975. The idea that CFCs could potentially be such a powerful force in global warming was also met with disbelief, not in the least from Ramanathan himself, who embarked on the project purely out of curiosity at a time when climate change was not a pressing concern.

Ultimately, Ramanathan established the now widely accepted fact that greenhouse gases other than CO2 are a major contributor to global warming, vitally important knowledge that underpinned the first successful climate mitigation policy.

The Royal Swedish Academy of Sciences on Thursday awarded Ramanathan, a distinguished research professor at the Scripps Institution of Oceanography at UC San Diego, the prestigious Crafoord Prize, which for some winners has been a harbinger of a Nobel Prize.

“He has expanded our view of how humankind is affecting the atmosphere’s composition, the climate and air quality and how these three interact,” said Ilona Riipinen, professor of atmospheric sciences at Stockholm University in Sweden and member of the committee that awarded the prize, which is worth 8 million Swedish krona (around $900,000).

Accidental climate scientist

Ramanathan, who studied engineering in Bengaluru, India, before moving to the United States, said his career’s first breakthrough was a result of several happy “accidents” that allowed him to connect the dots between different fields of study.

After graduating with a bachelor’s degree in engineering, he had spent an unhappy stint working at a refrigerator company making sure that the cooling agent — CFCs — did not leak. When he was 26, he moved to the United States and embarked on a doctoral degree at the State University of New York at Stony Brook in an engineering-related field.

Ramanathan, however, found his supervisor had unexpectedly switched focus, and his dissertation ended up detailing the greenhouse effect in the atmosphere of Venus. Then, while working at NASA Langley, he encountered the work of scientists Mario Molina and Frank Rowland. Their research showed CFCs depleted ozone, a natural atmospheric gas that protects humans from cancer-causing radiation. (The duo later won the Nobel Prize in 1995.) Not until the 1980s did CFCs broadly become a matter of public concern.

Before his 1975 investigation, Ramanathan said he wasn’t the least bit worried about climate change. However, as he and others expanded the list of trace gases, such as methane and nitrous oxide, that contributed to the greenhouse effect, Ramanathan became deeply concerned that global warming would manifest much earlier than prevailing thinking at the time. A paper he coauthored in 1985 concluded that trace gases were potentially as important as CO2 for long-term global warming.

“That made a big impact. The whole climate community sort of woke up and said, ‘Wait a minute. Global warming is going to come twice as fast as we thought. It’s not going to be your children’s problem. It’s your problem now,” said Spencer Weart, a historian of science and author of the book “The Discovery of Global Warming.” He is a former director of the Center for History of Physics of the American Institute of Physics.

“It’s great for Ramanathan to get some of the attention he deserves,” he added.

Ramanathan and others argued that CFCs’ potential for global warming gave reason to restrict production. The 1987 Montreal Protocol did eventually ban the use of CFCs, although largely because of intensified scientific and public concern over their health impact after the 1985 discovery of a hole in the ozone layer. Without that ban, the world could have seen additional warming of up to 1 degree Celsius (1.8 degree Fahrenheit), according to a 2021 study in the journal Nature.

The greenhouse effect of CFCs and trace gases was only part of the puzzle. In his long career, Ramanathan has deployed satellites, balloons, drones and ships to directly study Earth’s atmosphere, confirming with direct observations what climate models had only suggested.

His key findings include showing for the first time that clouds have a cooling effect on the planet and understanding how water vapor can amplify the warming effects of carbon dioxide. He also led a project that observed and measured a 3-kilometer (about 2-mile) thick cloud of air pollution that covered much of the Indian subcontinent. His work on atmospheric brown clouds revealed that air pollution had masked some of the effects of global warming, a complicated dynamic that scientists are still untangling today.

Ramanathan became a council member of the Pontifical Academy of Sciences in 2012, advising three consecutive popes on climate change policy, an experience he said made him consider not just the science but also the ethical implications of the climate crisis, which he emphasized will disproportionately affect the poor.

“His quiet but effective way of communication has been key to involving both the research community and decision makers,” said Örjan Gustafsson, a professor of biogeochemistry at Stockholm University and member of the Pontifical Academy of Sciences who has worked with Ramanathan.

“With an eye for the most vulnerable on our planet and an ear for younger researchers, he has inspired an entire generation of climate scientists.”

Ramanathan, now 81, drives a Tesla Model Y (although a red model of a Chevy Impala adorns his mantelpiece) and has converted his California home to solar power but gave up walking and taking the bus to work because, he said, it took too long.

He noted that he rarely counsels individual action to combat the climate crisis. Instead, Ramanathan encourages the young people he encounters to “stand up and elect the right politicians” and spread the word “using data-based, not junk, science.”

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