Bill Gates Discusses Human Welfare at the Heart of Climate Progress at Caltech

On Monday, November 3, 2025, Microsoft founder and philanthropist Bill Gates addressed more than 1,000 Caltech students, postdoctoral scholars, faculty, and staff at Beckman Auditorium speaking on his vision of climate resiliency that prioritizes human welfare.

"Tonight's turnout and the Beckman buzz here are testaments to Bill Gates's ability to capture the public imagination as an entrepreneur, as a businessman, an inventor grappling with implications of science and technology, and as a philanthropist concerned with human health and well-being across the globe," said Caltech President Thomas F. Rosenbaum, the Sonja and William Davidow Presidential Chair and professor of physics, in his introductory remarks.

Gates's presentation, which included a moderated discussion with Axios national energy correspondent Amy Harder and questions from students in the audience, was the capstone to a campus visit that included an in-depth look at sustainability research across campus. Among the topics covered in the presentations and lab visits included next-generation climate models, overcoming the traditional petroleum-based supply chain, solar fuels, and inorganic phototropic growth.

This was Gates's second visit to the campus in the last decade.

"The breadth of innovation we need to help the poorest in the world, including helping them deal with climate and minimize temperature increases, is so broad that most everyone at Caltech is working on something that can help us," Gates said in an Instagram post about his visit.

In his talk, Gates shared his approach to fostering innovation, sustainability solutions, and interventions that benefit human health and climate through his philanthropy. Specifically, he emphasized how a concern for human welfare must remain at the forefront of conversations about aid and funding, a core thesis of his October 28 memo published on the Gates Notes website.

"And so my lens here––and I suggest it should be the lens broadly––is while we reduce temperature increase as much as we can, whatever resources we have to help people adapt, that the real measure there is all the things we're doing to help the most vulnerable people on the planet in every single country," Gates said.

Gates reported that new emissions projections suggest a less extreme level of global warming than models from a decade ago, with temperatures now expected to rise by about 2 to 3 degrees Celsius instead of 4 to 5. He cited innovation as the reason for these lowered numbers and shared with the audience that he sees this innovation happening on Caltech's campus.

"You've got incredibly ambitious work across a lot of these areas going on right here at Caltech," Gates said. "I got to meet with the team that worked on the Space Solar Power Demonstrator, which is an incredible thing. And that idea of collecting [power] in space and then being able to beam it down, I thought of that as science fiction. But I have to say, when I met with that team today, it sounded like they are right on track, which would be a fantastic contribution."

Other Caltech innovations that Gates cited included plant science that could lead to improved drought-resistant and heat-resistant crops—which he had an opportunity to discuss with Trevor M. Nolan, assistant professor of biology and biological engineering, and his graduate students earlier in the day—and immunity research being done in the lab of Pamela Björkman, the David Baltimore Professor of Biology and Biological Engineering and a Merkin Institute Professor, that could lead to a universal vaccine.

At several points in the evening, Gates referenced topics of discussion and research shared during meetings with Caltech faculty earlier in the day, highlighting interesting new research thrusts, innovations, and potential applications from the labs of Tapio Schneider, Theodore Y. Wu Professor of Environmental Science and Engineering; Karthish Manthiram, Bren Professor of Chemical Engineering and Chemistry, William H. Hurt Scholar, and Executive Officer for Chemical Engineering; Nate Lewis, George L. Argyros Professor and Professor of Chemistry, among the others.

At the end of his speech, Gates took a moment to address the students, researchers, engineers, and scientists in the audience directly and underscored how they may be uniquely situated to address the issues that he had listed.

"I challenge you to think broadly about what we need to get done, how we direct our innovation, given the values we have and the priorities we have," Gates said. "We know the challenges: Make clean energy cheaper, make farmers more resilient, keep people healthy, help educate people. We don't yet know who will invent the solutions, but I bet some of you are sitting in this room."

During the moderated conversation, Harder invited Gates to address some of the specific controversy around and varying opinions on his October 28 memo, citing claims of the "false dichotomy" posed by his thesis and other interpretations by climate scientists. In response, Gates emphasized his focus on finite resources—monetary and otherwise—that he recognized in declining fundraising for vaccines at the Gavi Global Summit and how it encouraged him to write the memo. Gates emphasized that he would not withdraw financial support in areas outside of global health; rather, he is planning to increase his funding across the board.

"My funding for mitigation is going up. My funding for adaptation is going up. My funding for global health is going up. Now, I'm going to run out of money in 20 years. It's a total of $200 billion. That's what I've got," Gates said, earning the crowd's appreciative laughter at his honesty.

After the discussion, a handful of students asked Gates questions directly. Jessica Gonzalez, a graduate student studying experimental plasma physics, asked Gates about the role of students in academic institutions to address the challenges that Gates listed in his talk.

"Well, it is amazing in science how young people are key to new approaches," Gates responded. "I envy you in a way, being young at this time, because the speed of science that you can do as you [utilize] AI tools will be far greater than any time in human history."

To close out the evening, Harder asked Gates to answer a round of rapid-fire questions, which included the following exchange:

Harder: On a scale of one to 10, one being "not at all" and 10 being "completely," how optimistic are you about humanity in 2050?

Gates: It's my nature to be very optimistic. You can write a lot of things down about bioterrorism, nuclear weapons, polarization, or AI getting out of control that are kind of footnotes. But I still have this basic belief in innovation, and we'll adapt to these things. It's probably a perilous period, but I'd be hopeful.

Harder: So, what's your number, Bill?

Gates: Eight.