Lisa Rennels: Climate change in a different light

To understand Lisa Rennels’ work calculating the social and economic costs of climate change as a member of the second cohort of the Stanford Energy Postdoctoral Fellowship, do not read her many scientific publications – yet. Instead, peruse her impressive photography. 

Rennels invests close attention to color in her images of Northern California’s natural wonders. The images are lush with the vibrant colors of life. She also prefers the macro and the micro, not the in-betweens. The images are either intensely closeup, revealing easily overlooked secrets of the natural world, or they are step-back shots of impressive vistas. As a whole, they have a way of putting our beautiful, fragile world in perspective, much like her scientific work.

“Photography is something grounding for me,” Rennels says. “Working on climate and environment can be emotionally challenging. Photography helps me focus on the little, beautiful things … and slow down.”

Rennels’ published research studies have the same patterns of micro and macro, but in the context of what it truly costs society to have a planet that is warming by the day. 

These dualities – of intimate detail and big picture, intense emotion and cool logic – are threads in Rennels’ science and her art. Her technical research is anything but small-scale. It spans integrated assessment models, climate economic forecasting, and software engineering. Rennels is so enmeshed in the computational aspects of her work that she develops her own tools to do her economic modeling.

“I find coding very creative,” she explains. “You have a goal and then figure out how to get the computer to do what you want. I felt like I was building something. It’s fun to build tools that help others. And it’s really fun to build a community around them.”

Pre-med to environmental economics

She and her twin sister were born and raised in Palo Alto and came to love being in the California outdoors. She headed to Dartmouth as an undergraduate intending to be pre-med in the footsteps of her physician mother and father, but Rennels was soon taken with environmental studies and, particularly, environmental economics.

“I was initially drawn to economics not because I loved economics, honestly, but because it struck me as a language that more than we California hippies could speak,” she says of her desire to reach new audiences. Important audiences in the policy world might actually do something with the insights she was offering, she thought.

That led to work in environmental consulting in Boston, where she realized her existing programming skills were not flexible or powerful enough for the questions she wanted to ask, nor the answers she needed to know. Soon, Rennels was taking night classes in computer science at Tufts.

In her doctoral studies at the University of California, Berkeley, these threads again intertwined as she worked with Dr. David Anthoff, who is both a climate economist and computer scientist. There, alongside a team of researchers at Resources for the Future, UC Berkeley, and the Environmental Protection Agency, Rennels co-developed an entirely new integrated assessment model that estimated the social cost of carbon, methane, hydrochlorofluorocarbons, and other greenhouse gases. 

The EPA used the model as part of an effort to update the social cost of carbon used for federal regulatory analysis, and the work resulted in a paper in the journal Nature and a new federal standard that was more than three times higher than previous estimates.

“That work got quite a bit of attention, which was fun,” she says, while acknowledging that environmental health and economic growth are often at fundamental odds. “But this is the world we live in, and we’re trying to work within it.”

At Stanford, Rennels’ fellowship with the Precourt Institute for Energy continues this trajectory. She is advancing models to better represent the economic impacts of sea-level rise and examining adaptation strategies for a warming world. With faculty mentorship from both an energy systems modeler, Inês Azevedo, and an environmental economist, Marshall Burke, she’s expanding her skills in data science while staying rooted in the interdisciplinary interests that set her on this unique path.

Oh, and that love of color that is so evident in her photography? That’s never faded. It’s easily apparent in the data visualizations she loves to create. She admits: “We spend a somewhat shocking amount of time on that. But I enjoy it.”