Taro Takahashi, a seagoing scientist who made key discoveries about carbon dioxide and the earth’s climate, died Dec. 3 in Englewood, N.J. He was 89. In a career spanning more than 60 years, Takahashi and his colleagues documented how the oceans both absorb and give off huge amounts of carbon dioxide, exchanging it with the atmosphere. As a result, among many other things, scientists now know that a large part of modern humanity’s carbon emissions reside in ocean waters—at least for now.
Takahashi grew up in Japan before and during World War II, then moved to the United States as a young man, and adopted it as his country. He was one of the last surviving researchers of a mid-20th-century generation who discovered the basic workings of the planet’s climate system. His death, from the aftereffects of a stroke, was confirmed by Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y., where he spent much of his career.
When Takahashi began his work in the late 1950s, scientists faced a mystery. Burning of fossil fuels was sending great quantities of the greenhouse gas carbon dioxide into the air, but only about half of what researchers figured should be there could be found. Where did the rest go? By analyzing millions of shipboard measurements, Takahashi and his colleagues demonstrated that a quarter of emissions are absorbed by seawater; and by extension, another quarter must be taken up by the land. Takahashi’s findings laid the basis for many succeeding studies seeking to understand the dynamics of the greenhouse gas.
Taro Takahashi was born in Tokyo on Nov. 15, 1930. At that time, scientists had only begun to measure carbon dioxide in the air, then estimated to be not much above 300 parts per million. Much less was known about its presence in the ocean.
His father, Takezo Takahashi, was a mining engineer who had worked in the Texas oilfields during the 1920s. Takahashi’s mother, Tamako Takahashi, came from a family that owned a thriving hat-making firm. Both were great admirers of American culture. Takahashi’s father took over the family hat business, and with help from his U.S. contacts, positioned it as the sole Japanese distributor for Western-style Stetson hats. The young Takahashi, who attended private schools, came to be a fan of the New York Yankees and books such as Huckleberry Finn. Then, Japan attacked Pearl Harbor. “As kids, we were very confused by that,” he later said. Contacts with the United States were cut off. The hat business collapsed. Eventually, U.S. fire bombs leveled much of the Tokyo that Takahashi had known. In 1945, one of his uncles, a doctor at a Hiroshima hospital, disappeared without a trace when the United States dropped the atomic bomb.
Takahashi graduated from the University of Tokyo with a degree in mining engineering in 1953. In an oral history with the American Institute of Physics, he said that graduate school in the United States was a natural choice. Through an uncle, he met several Americans serving with the U.S. occupation forces, and they recruited him to apply to Columbia University. Moving to New York, he lived with family friends in their Upper East Side apartment. Takahashi at first struggled to learn English (along with German and Russian, required for his degree), but earned a PhD. in geology in 1957. He got to see his beloved Yankees in person. He recalled a visit to Philadelphia one cold winter day during his student years, where he came upon a copy of the Declaration of Independence on display. As he read the document’s ringing thesis of universal human rights, he began to choke up and cry. He became a U.S. citizen in 1961.
Takahashi hoped for a job in gold mining, but was sidetracked by a job offer from Maurice Ewing, the founder of Lamont-Doherty and then one of the world’s leading oceanographers. His first assignment: 10 months aboard the Vema, Lamont’s globe-circling research ship. As part of the 1957-58 International Geophysical Year, his job was to take measurements to see whether oceans were taking carbon dioxide from the air, giving it off, or doing some of both. Atmospheric CO2 was then up to about 315 parts per million, and scientists were just beginning to study the implications. Also on the project: Charles Keeling, a young scientist who went on to found the long-term air-sampling program that conclusively showed the curve of rising atmospheric CO2 in the 20th and 21st centuries. It was Takahashi who led the charge to establish the corollary facts about the oceans.
Takahashi’s 10-month cruise took him from New York to the coasts of Greenland, then down to Antarctica, and back up to South Africa. He was seasick much of the time, and slept below decks covered with a shower curtain to fend off seawater leaking through the wooden planks above him. When he got to Cape Town, Ewing cabled him instructions to disembark and set off on an another epic journey: an overland trip northward the entire length of Africa to Egypt. On this, he was ordered to take samples of plants and soils at numerous points. The aim was to help track the extent to which strontium-90 produced by then continuing nuclear bomb testing was collecting on land. (It turned out to be everywhere.)
In 1961, Takahashi published a paper based on his initial voyage. To a large degree, it laid out the basics of how the oceans interact with carbon dioxide in the air. He then quickly went on to lead efforts to pioneer new instruments and analytic techniques that allowed him and colleagues to fill out the details. One of his closest longtime colleagues was Lamont-Doherty geochemist Wallace Broecker, who is often credited with bringing the term “global warming” into the scientific lexicon. (Broecker died earlier this year.) In one project during the late 1970s and early 1980s, Takahashi and Broecker worked with the Exxon oil company to collect data on carbon dioxide in surface waters via monitors attached to oil tankers. Takahashi and his colleagues studied this data along with dozens of other datasets from universities and other institutions.
In the simplest form, they observed that the oceans take in large amounts of carbon dioxide from the air as cold waters sink around the Antarctic and Arctic. At the same time, waters recirculate and well up from the deeps nearer the equator, emitting some of the stored-up carbon dioxide back into the air, in a cycle that can take hundreds of years. But the process is a complex patchwork that can change or even reverse in places, depending on seasons, longer-term weather cycles such as El Niño, and changes in currents, winds and the abundance of plankton. In general, at least for now, the oceans are taking up more carbon than they give off; because of long-term accumulation, they now hold about 50 times more carbon than the air does. However, recent measurements suggest that the oceans may be tiring of compensating for human CO2 emissions, and that uptake may be slowing.
For many years, readings had to be collected and analyzed largely by hand, which required Takahashi or various graduate students to spend long stints at sea. But over the years, he and his team improved and automated the technology so that a human operator was no longer required. Many commercial ships now carry these automated instruments, and continue to collect readings.
During interims from Lamont in the 1960s and 1970s, Takahashi took up positions at Scripps Institution of Oceanography, California Institute of Technology, and New York City’s Queens College. While working as a professor at the University of Rochester, he met his eventual wife of 53 years, Elaine Ache, a geneticist and clinical social worker, whom he married in 1966. (For years, a rumor circulated among colleagues that previous to this, he had been engaged to the artist Yoko Ono, the eventual wife of Beatle John Lennon. In a 2018 interview, Takahashi said the story was “greatly exaggerated.” Yes, it was true that he had met Yoko Ono; her wealthy family moved from Tokyo to New York around the same time as he did. Takahashi happened to know her brother, and in 1956, the brother introduced them. He saw her just a few times; once, he invited her to join a group date with a few other Japanese expatriates at a Manhattan street-corner hamburger joint. “That was all, nothing else happened,” he said.)
Takahashi continued to spend time at sea until around 2003. After this, the newer technology he helped design made it easy for ships to relay data straight to his lab, and he mostly stayed home. On the side, he dabbled in studies of how carbon dioxide might be removed from industrial smokestacks and stored under the seabed, and got involved in colleagues’ experiments aimed at understanding the chemistry of the earth’s mantle, and the core of the moon. In all, he authored or coauthored some 250 scientific papers.
Takahashi’s attitude toward climate evolved with time. In the early 1990s, he and four other Lamont scientists including Broecker met with then U.S. senator Al Gore. Gore wanted to discuss the growing evidence of carbon dioxide-driven global warming, and what could be done about it. At the time, Takahashi said, he could not “crank up the fervor as much as Gore.” He added: “Although I’m aware of the dangers of runaway global warming, “[I’m] not totally committed to say that’s a bad thing. Two degrees warmer, is this really negative to human beings?”
Over succeeding years, he changed his mind. In 2009, he coauthored a global report showing that human CO2 production had reached a new high—one that has since been exceeded multiple times. By then, he called reduction of carbon emissions “a very urgent task” for humanity. In 2010 he received the United Nations’ Champion of the Earth Award for environmental leadership. He said in a UN video that “the major question now is whether the oceans will continue to play a role” in offsetting human activity. He called for more efficient cars and power plants along with technology to capture CO2 from the air as part of the antidote.
Takahashi continued working on new research until a bout of poor health sidelined him for a few weeks before his death. He recovered and was about to return to work, when he suffered the stroke in the middle of the night that killed him. Always interested in cosmology and humanity’s place in the universe, he had just started re-reading Stephen Hawking’s A Brief History of Time that evening; his daughter, Suzi Takahashi, said a bookmark showed he had made it to page 16 before retiring.
He is survived by his wife; his son Timothy Takahashi, a professor of aerospace engineering at Arizona State University; daughter Suzi, an acting professor and theater director in New York; and his sister Yoko Yamada and brother Katsuo Takahashi, both living in Japan.
At the time of his passing, global atmospheric CO2 measured nearly 411 parts per million, and was projected to keep rising.