She Walks the Line

Climate scientist Katharine Hayhoe (Image by Sydney Gawlik)

Inside an airport hotel ballroom in Austin, Texas, Katharine Hayhoe, MS ’97 LAS, PHD ’10 LAS, takes the stage at the 29th Texas Land Conservation Conference. Rather than jump into graphs and charts, she asks everyone to use their phones to capture a QR code, which opens an interactive poll.

“How would you describe what you do?” she asks. “One word.”

Answers populate the screen: Conservation, communications, advocacy, stewardship, water, trees, restoration, carbon, horticulture, ecology, anthropology.

“I love this,” says Hayhoe, who is in her early 50s, with long, straight hair and a bright smile that lights up her face. “I love the diversity here because we need all of this. None of us can do this work by ourselves.”

Such diversity is near to her heart because she embodies what many think of as polarized camps: Christian evangelist and climate change scientist. Yet for Hayhoe, raised by Christian missionaries in Colombia and later in Canada, her faith propels her science. In 2019, she wrote in an op ed in The New York Times, “I chose what to study precisely because of my faith…. To me, caring about and acting on climate was a way to live out my calling to love others as we’ve been loved ourselves by God.”

Straddling another divide, Hayhoe also is a professor and advocate for climate science in Texas, a state where the land, politics and economy are dominated by oil and gas. If Texas were a country, its carbon emissions would be 11th in the world, just below that of Saudi Arabia. Yet, the room full of nearly 400 Texas ranchers, conservationists and government employees who work to protect the state’s lands are riveted by her warm and thoughtful discourse. Hayhoe is deeply committed to reaching across society’s silos—in fact, she believes it is the only way forward. It’s a tenet that’s guided her career, and its roots are at the University of Illinois.

The engaging opener at the conservation conference is typical for Hayhoe, whose ability to frame complex scientific issues in simple terms and appeal to the deeper human values that underpin them has made her one of the most powerful voices addressing climate change today. From 2017 to 2019, she hosted a PBS Digital Series called Global Weirding and has authored several books, including Saving Us: A Climate Scientist’s Case for Hope and Healing in a Divided World (Simon & Schuster, 2021). Her TED talk, “The Most Important Thing You Can Do to Fight Climate Change: Talk About It,” has generated more than 4 million views.

Hayhoe’s scientific work has garnered too many accolades to list here. Her peer-reviewed articles top 150; she was a lead author for the 2nd, 3rd and 4th National Climate Assessments, and author for the 5th. In 2019, Hayhoe was named a United Nations Champion of the Earth in Science and Innovation. In 2023, she was named to the American Academy of Arts and Sciences. She is chief scientist at The Nature Conservancy.

Hayhoe’s illustrious scientific career started as a double major in physics and astronomy at the University of Toronto. She took a new class during her junior year on the science of climate change and discovered her training in the science of other planets also gave her the skills to study the Earth’s atmosphere. Even more, she had an immediate connection to the subject because “climate change is not just an environmental issue, it’s a human issue.”

For her master’s degree, Hayhoe decided to apply to 10 schools, and she had pinned down the first nine. For the 10th, she wavered between Ohio State and Illinois.

It was 1994 and Don Wuebbles, ’70 ENG, MS ’72 ENG, had just joined Illinois as department head of atmospheric sciences after 20 years at the University of California, Lawrence Livermore National Lab. There, he had developed a stratospheric model of air quality to study ozone in the wake of the Montreal Protocol. That historic agreement remains an iconic example of the world joining forces to solve a global atmospheric problem. It was exactly the kind of work that Hayhoe wanted to do.

But Hayhoe didn’t know Wuebbles was at Illinois. His appointment was so recent that it hadn’t yet made it onto the website. What tipped the balance for Illinois for Hayhoe was its sailing club team and graduate student Christian Fellowship. Both of those would shape her life.

“I was so intrigued by her application that I immediately contacted her and told her I would like to discuss having her be a graduate student,” Wuebbles recalls. “We hit it off, and soon after that, she accepted. Her master’s degree resulted in something like three papers. I mean, this [was] not your usual master’s degree.”

Indeed, it was a lot more like a Ph.D., though Hayhoe was adamant that she didn’t want to pursue the higher-level degree. As a teen, her father had worked nights to finish his doctorate. “I felt like I had done a Ph.D. by proxy. And the last thing I wanted to do was another one.”

Hayhoe admired how Wuebbles collaborated with colleagues across the university, in industry and in the government, and that he actively made space for women in what is traditionally a male-dominated field. “Don was there for me through it all,” Hayhoe says. “Giving me advice, contacts, encouraging me. If I hadn’t had that foundation at Illinois, I don’t think I’d be where I am now. It’s not an exaggeration.”

By her second year, Hayhoe was organizing the weekly meetings of the graduate Christian Fellowship, which emphasized connection across faith backgrounds. “Every week, a professor would come speak. They could be Catholic, Protestant, Orthodox, whatever. It was just cool for people to reflect on how their work influenced their faith.”

One of those evenings, Hayhoe noticed a new guy in the back, sitting next to her roommate, who was shy and not likely to start a conversation. “I figured, okay, I have to go talk to him. So, I introduced myself…and ended up marrying him.”

Her husband is Andrew Farley, PHD ’00 LAS, who was studying linguistics and today is an evangelical minister. She joined the sailing team, which often met at Lake Clinton, the cooling pond for the Clinton Nuclear Generating Station. “It was always very warm. Hopefully, I’m not radioactive,” she says with a wry smile.

Katharine Hayhoe’s ability to translate complex scientific issues in simple terms has made her a sought-after guest speaker and interview subject. (Image by Amanda Stronza/Getty Images)

Back at the conference, Hayhoe moves from interactive quizzes to a photo of a pencil-straight road between Lubbock and Amarillo. Driving along a road like this, she says, she was thinking very hard about climate change and came up with a metaphor to describe our behavior.

“That road is so straight that you could pretty much stay on the road by looking in the rearview mirror.” She jokes, “I do not recommend it.”

But her point is serious. Our society is built on the assumption that the climate is stable and the past reliably predicts the future. Building codes, crop yields, water planning and energy demand are all based on the past. “The problem we’re seeing today,” Hayhoe says, “is the speed of the change.” She flips to a graph showing the number of billion-dollar weather events in Texas starting in 1980 through 2024, adjusted for inflation. Before 2006, no more than five occurred in a single year. In 2023, there were 16. In 2024, there were 20.

Although Wuebbles encouraged her to stay at Illinois to earn a Ph.D., she resisted, choosing instead to help others prepare for the impact of climate change. The consulting business she developed, ATMOS, created tools to predict how climate change would affect cities and regions, and how they could respond.

When Texas Tech offered her husband a tenured position, he asked if they would also provide a research professorship to Hayhoe. They agreed, and the couple left the verdant fields of the Midwest for the scrubby plains of Lubbock.

As a research scientist, Hayhoe was funded by “soft money”—meaning she didn’t receive a salary from the university but instead had to win grants or contracts. That was fine because her work was going well. Her cutting-edge research on climate change was being published in prestigious journals such as PNAS and Science.

In 2007, when the International Panel on Climate Change was awarded the Nobel Peace Prize, Hayhoe was the only Texas Tech climate scientist who had contributed to the IPCC’s work.

At Texas Tech, the dean called Hayhoe into her office and asked her why she didn’t have her Ph.D. “We can’t make you a tenured professor without it,” she told Hayhoe, who finally accepted that she needed the degree—and the guaranteed salary that came with it—though it took a Nobel Prize to convince her.

Hayhoe called Wuebbles who happily accepted her back to his lab. She had been developing a tool called “downscaling,” in which observational data could make lower-resolution global models more accurate, and the research was ample for a dissertation. While working on her masters, she’d already completed the classwork and residency requirements. But she would need to pass qualifying and preliminary exams.

Bob Rauber, the chair of the department, sat on Hayhoe’s qualifying exam committee. He said she was one of the most brilliant students he’d known. “She just smoked all the questions.”

That was May. In August, Hayhoe passed her preliminary exam. She completed her dissertation that winter, all in just 11 months. And, she and Farley had a baby boy shortly before she began, who was still a toddler when she finished. That whirlwind would have left almost anyone depleted and spent, but she remembers this time fondly because of the flexibility and support she received at Illinois.

Doctorate in hand, Hayhoe returned to Texas Tech to claim her promised tenure. Hayhoe and Farley had published the book, A Climate for Change: Global Warming Facts for Faith-Based Decisions (FaithWords, 2009), and not long after, she was invited on Fox News to promote it.

Texas Tech is situated in the middle of Texas’ oil fields, and it has deep connections to the fossil fuel industry. Hayhoe’s appearance on Fox News put her in the political crosshairs. The school started receiving complaints from alumni who had watched the segment. Not soon after, Hayhoe’s tenure offer was rescinded. “I was devastated,” she says. “I had just gotten my Ph.D. and now the whole carpet is being pulled out from under my feet.”

“I chose what to study precisely because of my faith…. To me, caring about and acting on climate was a way to live out my calling to love others as we’ve been loved ourselves by God.”

As benefits someone who values cross-collaboration, Hayhoe received help from outside her field. Just after the tenure denial, Hayhoe was invited to give a seminar in Texas Tech’s political science department. The next week, the department chair knocked on her office door and asked if she’d ever consider moving to political science. Unbeknownst to Hayhoe, her talk had been a job interview.

Having just experienced the power of politics herself, Hayhoe was ready. “I wanted to know more about [the science of politics] because that’s where the barriers are,” she says.

In the political science department, Hayhoe found the kind of warm academic home that she had enjoyed in atmospheric sciences at Illinois. Today, she is fully tenured, and holds a distinguished professorship and an endowed chair.

And she’s even starting to see shifts when it comes to the dogma of skepticism about climate change in the church. Last fall, Hayhoe was invited to give a keynote at the Lausanne Congress, which was founded by Christian leaders Billy Graham and John Stott. The meeting was held in Incheon, South Korea, and was curated to bring together 10,000 evangelical leaders from around the world. Attendees were seated at tables of six to accommodate one person from every continent, leading to powerful conversations about the most pressing global issues for Christians.

Hayhoe had heard that some American leaders weren’t pleased that this Christian conference would feature a prominent talk on climate change. But “it was a wonderful opportunity for Christians around the world to actually have conversations with personal witnesses who had been impacted by climate extremes,” Hayhoe says. “I’m just so excited about that. I feel like things are moving. The American church is obviously dragging at the tail. But around the world, the church is really getting activated. Ten years ago, I would have never dreamed of having this kind of opportunity.”

Back at the ballroom, Hayhoe is wrapping up her talk. She projects a map of Texas on the screen showing the results of a question from a Yale study on perceptions of climate change. Each county is colored to represent the proportion of the population who said they discuss global warming, at least occasionally. The deeper the blue, the fewer people are talking about climate change. The entire state is the color of a bluebonnet.

Having conversations, she says, is how people connect all the data that’s in our heads to our hearts. “Why do you protect your land?” she asks. “Why do you conserve it? Love. We might not be comfortable saying that word, but it’s the reason. If what we love is at stake, then what are we waiting for? You know what to do. Have a conversation today.”

Collectively, the room stands in ovation. It feels like a tangible demonstration of Hayhoe’s aim: bringing diverse groups together in the face of climate change.

Among the audience questions that follow, Hayhoe fields one about the new Trump administration, which has already begun dismantling climate change initiatives. In response, she likens mitigating climate change to pushing a boulder. “Millions of people are already pushing it in the right direction,” she says. “What the federal government does will change the slope underneath the boulder. Right now, it’s a bit more uphill. But that doesn’t mean we should give up.”

Hayhoe comes back to her faith, which gives her the courage to stand up to the powerful forces that have tried to stymie her career and silence her voice. “If God has given me the abilities to understand the physics of the Earth, and the interest to pursue it, how can I not use these skills to try to make a difference in real people’s lives today? I’ve known since day one that my motivation is love,” she says. “And if your motivation is love, you might be discouraged; you might be beaten down; you might have to take breaks; you might question what you’re doing. But ultimately, if it’s love, you have to keep going.”

(Image by Urs Flueeler)

Her Magnum Opus

Katharine Hayhoe’s research focuses on making data drawn from different climate models more useful and accessible

Climate scientist Katharine Hayhoe works at the interface between large-scale global climate change models, or GCMs, and local models that provide the information people need in a warmer, weirder world. Because of Earth’s complicated physics, GCMs run at coarse scales of time and space. “We don’t have powerful enough computers to run global projections at a really granular scale yet,” she says. “It would take longer to run the projections than to just wait for the future to happen.” But those gross scales aren’t relevant to local issues.

The connector between GCMs and local models is a statistical method called downscaling. For her dissertation, Hayhoe surveyed all of the downscaling methods available and discovered gaps she’s been working to fill ever since. For example, some entities, like water managers, measure their data in grids, while others measure repeatedly at a single location, or station. But downscaling tools couldn’t handle both. Also, different downscaling methods were used in different parts of the world.

The culmination of Hayhoe’s work resulted in the Seasonal Trends and Analysis of Residuals empirical statistical downscaling model (STAR-ESDM).¹ It not only brings standardization to all the other models, it also runs on a desktop computer. And, it’s fast. “You can use it anywhere in the world. You can use it for any kind of data: weather station data, grid data, even satellite data,” Hayhoe says. “It’s really my magnum opus.”

STAR-ESDM has already been used to help lay out plans for the City of Houston² and in the most recent National Climate Assessment.³ They also developed interactive story-map websites that make those climate predictions easy to access and understand, even for people not familiar with climate modeling.

Indeed, Hayhoe has also pioneered making climate science accessible to the general public. One example: GCMs output is a unit of Watts per square meter (W/m²), which means nothing to most people. So Hayhoe has pushed to convert results to degrees of temperature. “It’s making sure the results are also translated to something that’s meaningful to people,” she says. “I see that as part of my science work, too.” —J.B.

1. Hayhoe, K., Scott Fleming, I., Stoner, A., & Wuebbles, D. J. (2024). STAR-ESDM: A generalizable approach to generating high resolution climate projections through signal decomposition. Earth’s Future, 12, e2023EF004107.  2. Houston Climate Impact Assessment 2.0 Understanding Houston’s Past and Future Climate and What it Means for You. Prepared for the City of Houston May 27, 2022  3. ATLAS of the 5th National Climate Assessment