Mark Thiemens (M.S. ’74) was inducted into the – the United Kingdom’s national academy of sciences – earlier this month in London. He was one of 21 new foreign members elected to the 364-year-old society whose past inductees include Isaac Newton, Ernest Rutherford, Albert Einstein, Charles Darwin and Stephen Hawking.

Thiemens studied oceanography at and is now a Distinguished Professor of Chemistry and Biochemistry at the University of California San Diego (UCSD).

“I want to make the point that played a real role in this process,” he said.  

Already a notable scientist and member of the U.S. National Academy of Sciences, the American Academy of Arts and Sciences and numerous National Resource Council boards, Thiemens’ induction signifies his invaluable contributions to science with worldwide implications. 

This year, he joins; former Chief Medical Advisor to the U.S. President, Professor Anthony Fauci; Nobel laureate, Professor Emmanuelle Charpentier and more than 90 scientists worldwide as international members of the Royal Society. The new inductees come from various disciplines including academia, medicine, engineering science industry and society at-large. During the three-day ceremony, Thiemens added his name to the society’s official record book. The Fellowship of the Royal Society is the oldest scientific academy in continuous existence.

Sir Adrian Smith, president of the Royal Society, said, “I am pleased to welcome such an outstanding group into the Fellowship of the Royal Society. This new cohort has already made significant contributions to our understanding of the world around us and continue to push the boundaries of possibility in academic research and industry. From visualizing the sharp rise in global temperatures since the industrial revolution to leading the response to the Covid-19 pandemic, their diverse range of expertise is furthering human understanding and helping to address some of our greatest challenges. It is an honor to have them join the Fellowship.”

Thiemens is best known for his discovery of the mass-independent isotope effect, which has improved scientific understanding in areas as diverse as the origin of the solar system and the accumulation of greenhouse gasses. His work helped developed the first means by which the origin of life may be quantified from the earliest rocks at 3.8 billion years ago to 2.2 billion. This work led to his selection as the 1998 Ernest O. Lawrence Medal winner, the most prestigious award given to scientists by the U.S. Department of Energy.

Thiemens’ scientific interests also include climate change.

“Just before COVID-19, I came up with a technique where we can measure the melting rate of ice without having to go out every year, but we can measure the river water by using a radioactive nationally produced method,” he said.

He also spent 10 years in-and-out of Tibet studying freshwater flow from Mount Everest to India, China, Pakistan, Vietnam and Cambodia.

“If that melting rate is fairly quick and that water goes away, you know there are going to be problems,” Thiemens said. “I help them predict how they should be managing their water.”

As a professor, Thiemens said he uses his enthusiasm for science to inspire his students to figure out the unanswered questions of the scientific world.

“We've had astronomy for 600 years, and we don't even know what 80% of the universe is made from. How's that for a big problem?” he said. “We can't balance the carbon cycle on Earth, even though people have been studying it for 60 years. I tell my students. ‘Here's some big stuff for you to work on,’ and that way, it makes it more interesting.”

Thiemens’ curiosity stems from his mother and father. His parents didn't get to go to college because of World War II. 

“They lost five years of their lives either going and flying in bombers or staying home and working in factories,” he said. “And they were curious, and they were interested in everything. In Virginia, if there was a new bridge being worked on, we'd have to go see it, have some theories about why they're building it this way.”

Reflecting on his induction into the Royal Society, Thiemens recalled a childhood memory when he came home to tell his parents about a home run he hit during a baseball game.

“My dad commented, ‘That's great Mark,’ and then he said in a kind way, ‘You know, for things that are really good, you don't have to brag as they will know.’”

It turned out the neighbors had already told his parents.

“His point was well taken and a very good message from a very humble gentleman,” Thiemens said.