MAPPING 66 MILLION YEARS OF ATMOSPHERIC CO2 CHANGES

by BRIAN MAFFLY

TODAY, ATMOSPHERIC CARBON DIOXIDE IS AT ITS HIGHEST LEVEL IN AT LEAST SEVERAL MILLION YEARS THANKS TO WIDESPREAD COMBUSTION OF FOSSIL FUELS BY HUMANS OVER THE PAST TWO CENTURIES.

But where does 419 parts per million (ppm)—the current concentration of the greenhouse gas in the atmosphere—fit in Earth’s history?

That’s a question an international community of scientists, featuring key contributions by University of Utah geologists, is sorting out by examining a plethora of markers in the geologic record that offer clues about the contents of ancient atmospheres. Their initial study reports on reconstructed concentrations going back through the Cenozoic, the era that began with the demise of dinosaurs and the rise of mammals 66 million years ago.

Glaciers contain air bubbles, providing scientists direct evidence of CO2 levels going back 800,000 years, according to U geology professor Gabe Bowen, one of the study’s corresponding authors. But this record does not extend very deep into the geological past. “Once you lose the ice cores, you lose direct evidence. You no longer have samples of atmospheric gas that you can analyze,” Bowen says. “So you have to rely on indirect evidence, what we call proxies . . . tough to work with because they are indirect.”

These proxies include isotopes in minerals, the morphology of fossilized leaves and other lines of geological evidence that reflect atmospheric chemistry. One stems from the foundational discoveries of U geologist Thure Cerling, himself a coauthor on the new study, whose past research determined carbon isotopes in ancient soils are indicative of past CO2 levels.

But the strengths of these proxies vary and most cover narrow slices of the past. The research team set out to evaluate, categorize, and integrate available proxies to create a highfidelity record of atmospheric CO2

“This represents some of the most inclusive and statistically refined approaches to interpreting CO2 over the last 66 million years,” says co-author Dustin Harper, a U postdoctoral researcher in Bowen’s lab. “Some of the new takeaways are [that] we're able to combine multiple proxies from different archives of sediment, whether that’s in the ocean or on land, and that really hasn’t been done at this scale.”

The new research is a community effort involving some 90 scientists from 16 countries. The group hopes to eventually reconstruct the CO2 record back 540 million years to the dawn of complex life.

Having a reliable map of past CO2 levels could help scientists more accurately predict what future climates may look like, says William Anderegg, director of the U’s Wilkes Center for Climate Science & Policy.

“This is an incredibly important synthesis and has implications for future climate change as well, particularly the key processes and components of the Earth system that we need to understand to project the speed and magnitude of climate change,” Anderegg says.

“Eight million years ago," says Bowen "there’s about a five percent chance that CO2 levels were higher than today. But really we have to go back 14 million years before we see levels we think were like today.”

A more refined understanding of past trends in CO2 is therefore central to understanding how modern species and ecosystems arose and may fare in the future, the study states.

A longer version of this story first appeared in @TheU.

THE ALSAM FOUNDATION HAS MADE A SUBSTANTIAL GIFT TOWARD THE LATEST ADDITION TO THE SCIENCE CAMPUS AT THE U: THE L.S. SKAGGS APPLIED SCIENCE BUILDING .

The 100,000-square-foot building will include modern classrooms and instruction spaces, cutting-edge physics and atmospheric science research laboratories, and faculty and student spaces. Scientists in the new building will address urgent issues, including energy, air quality, climate change, and drought. The building’s naming honors L.S. “Sam” Skaggs, the philanthropist and businessman whose retail footprint spread from the Mountain West to the rest of United States.

Expressing profound gratitude for the transformative gift, Peter Trapa, dean of the College of Science, says, “We deeply appreciate The ALSAM Foundation’s extraordinary generosity. This gift is a testament to the value the organization places on higher education and its transformational impact on students and communities. It continues the Skaggs family's legacy in Utah and at our state’s flagship university. The new L.S. Skaggs Applied Science Building, a beacon of scientific innovation, will play an essential role in educating students in STEM programs throughout the University of Utah. This much-needed building allows the U to expand its STEM capacity and continue to serve our region’s expanding workforce needs.”

The construction of the L.S. Skaggs Applied Science Building is part of the Applied Science Project, which also includes the renovation of the historic William Stewart Building. The overall project is scheduled to be completed by next summer. Combined with the Crocker Science Center and a new outdoor plaza abutting the historic Cottam’s Gulch, the three buildings and outdoor space will comprise the Crocker Science Complex named for Gary and Ann Crocker.

The Skaggs family has a long history of supporting universities through The ALSAM Foundation, including the U. Other ALSAM Foundationsupported projects at the U include the L.S. Skaggs Pharmacy Research Institute, housed in the Skaggs Pharmacy Building, and the Aline S. Skaggs Biology Building, named after Mr. Skaggs’s wife.

The Foundation issued the following statement, “The ALSAM Foundation and the members of the Skaggs family are pleased to continue the legacy of Mr. Skaggs at the University of Utah. The Applied Science Project will benefit STEM education which was one of the goals of Mr. Skaggs.” <

AS A HIGH SCHOOL STUDENT AT OLYMPUS HIGH IN SALT LAKE CITY, CO-FOUNDER AND FORMER CEO OF ADOBE JOHN WARNOCK , WHO PASSED AWAY LAST AUGUST AT AGE 82, FOUND A MENTOR IN MATH TEACHER GEORGE BARTON. “HIS APPROACH WAS REALLY QUITE SIMPLE,” WARNOCK ONCE RECALLED.

“He instructed us to pick up a collegelevel textbook for algebra, solve every problem in the book, then move on to the next subject, trigonometry, and do the same. And after that, go on to analytic geometry. By following his advice and solving a lot of problems,

The auspicious career of Warnock and other brilliant University of Utah alumni who changed the world through computer science was in high relief last year when a sampling of the scrappy and now legendary bunch assembled on campus to commemorate their roles as 3-D graphics pioneers. The occasion was a celebration of 50 years of the U’s Kahlert School of Computing, and Warnock was presented with an IEEE Milestone award.

But before he was known as the co-founder with the late Charles Geschke of Adobe, Warnock was propelled by his high school teacher into the U’s math department. There Warnock earned a BS and MS in mathematics before decamping to the College of Engineering where he earned a PhD in electrical engineering/ computer science. It was an exciting time. The U was one of 15 renowned universities that had a contract with the Advanced Research Projects Agency, prompted by the worrisome launch of the Russian Sputnik satellite during the Eisenhower era. A node on the original Internet known as ARAPNET, the U was the first university to offer online registration to its students, and Warnock, as part of his dissertation research was busy at work, just days (and long nights), ahead of when the portal dropped, having developed the recursive subdivision algorithm for hidden surface elimination. That algorithm, named after Warnock, made computer graphics possible.

Twenty-five years post Sputnik, Adobe appeared, which, inarguably, lofted desktop publishing into the stratosphere with its soon-to-launch PostScript language. The information technology sector has never been the same since, epitomized by Warnock’s appeal to the U students during the 2020 commencement: "The rest of your life is not a spectator sport. Your job in life is to be an active player, to make the world a better place.”

Warnock is survived by his wife and three children. <