Konrad Steffen, Who Sounded Alarm on Greenland Ice, Dies at 68

Konrad Steffen, an Arctic scientist whose work showed that climate change is melting Greenland’s vast ice sheet with increasing speed, died on Saturday in an accident near a research station he created there 30 years ago. He was 68.

Police investigators said he had fallen into a crevasse in the ice and drowned in the deep water below.

A fellow scientist at the station, Jason Box, said the crevasse, or large crack, was a known hazard. But he added that high winds and recent snowfall had made visibility poor and landmarks harder to spot.

The small group at the site — christened Swiss Camp by Dr. Steffen — was installing new equipment when he walked off to perform another task. Over the next few hours, Dr. Box said, they assumed that Dr. Steffen had gone back to his tent for a nap. But when they finished their work he was nowhere to be found.

Ryan R. Neely III, a climate scientist at the University of Leeds who studied under Dr. Steffen, said that not long ago crevasses in the area where Dr. Steffen was working “were unheard-of,” but that they had begun emerging with the stresses on the ice sheet created by warming.

“In the end,” he said, “it looks like climate change actually claimed him as a victim.”

Dr. Neely called his old mentor (“Koni” to his friends) a “larger than life explorer-scientist that you typically only get the chance to read about.”

Understanding Greenland’s ice sheet is crucial to understanding climate change and sea level rise. Current projections say that if the planet warms by two degrees Celsius (3.6 degrees Fahrenheit) over preindustrial times, average sea levels will rise by more than two feet, and 32 million to 80 million people will be exposed to coastal flooding.

Greenland’s ice sheet, more than a mile thick, is the second largest mass of freshwater ice on the planet, after Antarctica. It is already a major contributor to the sea level rise.

Richard B. Alley, a professor of geosciences at Pennsylvania State University, called Dr. Steffen “a giant in the field,” although his scientific work was not, he allowed, “sexy.” Dr. Steffen focused on such tasks as measuring the balance of snowfall and ice melt and maintaining weather stations.

He had a gift for translating that science for nonspecialists, including journalists, “letting the public and policymakers know what we know,” Dr. Alley said. Dr. Steffen served on influential bodies like the United Nations Intergovernmental Panel on Climate Change.

Dr. Steffen built the Greenland outpost in 1990, choosing a spot on the ice sheet’s barren reaches at an elevation of about 3800 feet. Over time, he developed a network of monitoring stations and made the camp a destination for journalists, political leaders and other dignitaries to see climate change from the front row. (He crowed over small luxuries like his bread maker.)

One visitor, former Vice President Al Gore, posted a tweet on Monday stating that “Koni’s renowned work as a glaciologist has been instrumental in the world’s deepened understanding of the climate crisis.”

Waleed Abdalati, a former graduate student under Dr. Steffen and his successor as the current head of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder, recalled his first trip to Swiss Camp, where, riding with Dr. Steffen, he set down on the ice in a helicopter.

As soon as it was safe to leave the craft, Dr. Steffen leapt out. “He opened his arms wide and looked up at the sky with a huge grin on his face, and was just drinking in the Arctic air,” Dr. Abdalati said. “I looked at him and saw a man at home.”

He added: “He died in a place he loved, doing what he loved. He died at home.”

Dr. Steffen returned to the camp almost every year, maintaining it as the ice melted beneath; it has had to be rebuilt repeatedly and was again in precarious condition this year.

In his book “The Ice at the End of the World,” the journalist Jon Gertner wrote that by 2017, Dr. Steffen’s measurements suggested that the ice had dropped by nearly 40 feet at Swiss Camp. In lectures, he would joke that he would sell the station for a dollar.

Conditions were spartan. “Since we all shared the same tent for sleeping, it was a challenge for me because of the snoring,” said Julienne Stroeve, a professor at the University of Manitoba in Canada and the first woman to be invited to the camp, in 1993. When she returned to the site in 2000, she said, she brought her own tent.

Konrad Steffen was born on Jan. 2, 1952, in Zurich to Ernst and Maria (Kurzinski) Steffen. His mother ran an accounting firm; his father was a fashion designer.

Growing up, he told Mr. Gertner in 2015, “I wanted to become an actor, actually. But my dad said, You get a profession first, then I’ll pay for acting school.” He studied engineering instead. “I just loved what I did,” he said.

He received his undergraduate degree in 1977 and a Ph.D. in natural sciences in 1984, at E.T.H. Zurich, the Swiss Federal Institute of Technology.

Dr. Steffen went to the United States in 1986 as a visiting fellow at the Cooperative Institute in Boulder. He rose to director in 2005 and served in that post until 2012, when he became director of the Swiss Federal Research Institute for Forest, Snow and Landscape Research WSL.

In 1984 he married Regula Werner, who died in 2011. They had two children, Anico Tabea and Simon Alexander. In 2017 he married Bianca Perren, who survives him, as do his children and a sister, Rose Marie Stouder.

Simon Steffen was at the Swiss Camp with his father when the accident occurred.

Dr. Steffen told Mr. Gertner that the accumulating risks of climate change had not yet sunk in. If people hear that scientists have projected that warming will increase by two degrees by the year 2100, he said, they might dismiss it, saying “two degrees is not so bad.”

But that is only the start, he warned. “Sorry,” he said. “It won’t stop there. The melting won’t stop there. The curve gets steeper and steeper.”

Dr. Box said he wanted to return to the site next year. “We’ve got to keep the measurements running,” he said.