“The climate crisis has moved into everyday life and it can feel overwhelming,” atmospheric scientist Peter Kalmus writes in a September op-ed for the Los Angeles Times. But now is not the time for “we’re doomed” nihilism, he adds. “No matter how bad it gets, we must keep doing everything we can to keep it from getting worse.”

Kalmus, who works at NASA’s Jet Propulsion Laboratory (he speaks here on his own behalf), is the author of the 2017 book Being the Change: Live Well and Spark a Climate Revolution. The book chronicles his efforts to cut his personal fossil fuel usage; he now generates roughly two metric tons of CO2 equivalent per year, in contrast to the average American’s 20. He writes about modifying a 1980s Mercedes to run on waste vegetable oil and about practicing “freeganism”—dumpster diving at grocery stores to rescue produce that would otherwise be wasted. But he warns that individual reductions are not enough. “We also need collective action on a large scale if we hope to quickly reduce global carbon emissions and avoid increasingly catastrophic warming.”
PT: How did you get started in climate science?
KALMUS: I got my undergraduate degree in physics, with a goal of doing cosmology. But I didn’t feel ready to go straight to grad school. I taught high school for two years and met the person I ended up marrying, and we moved to New York City. I got a job programming on Wall Street. I didn’t find it meaningful writing trading platforms that help superrich people get richer. So I moonlighted as a volunteer at a cosmology lab at Columbia for about a year, took the GRE, and applied to grad school. As a grad student I worked for LIGO [the Laser Interferometer Gravitational-Wave Observatory], contributing to detector calibration and gravitational-wave burst searches.
But in the middle of my PhD, in about 2006, I went to a colloquium by [climate scientist] Jim Hansen. It really woke me up. I just couldn’t—I still can’t—wrap my head around how the facts about climate change can be out there and people, even scientists, can still go about their day without really being concerned about it.
I got an offer to do an atmospheric science postdoc at the Goddard Institute for Space Studies. But my career at LIGO was going really well, and I was excited to move to California, so I took a postdoc at Caltech instead. But the floodgate was already open. I kept reading the peer-reviewed literature and learned more about climate breakdown and got increasingly concerned. Once you realize this is happening, you can’t unsee it. After a couple of years I realized I just couldn’t concentrate on astrophysics anymore. And so I finally made the field switch to atmospheric science and started working at JPL.
PT: What are you currently working on?
KALMUS: I started in atmospheric science thinking about clouds, especially low clouds, and how we might be able to observe them and model them better. I work with data from AIRS—that’s the Atmospheric Infrared Sounder, an instrument in space. I’ve been frustrated by dealing with data from individual satellites, so I’m working on a data fusion pilot project to combine multiple sets of complementary data from AIRS and similar satellite instruments into one product.
A second project uses AIRS and other satellite infrared sounders to observe severe storms, such as tornadoes and hailstorms from supercells, from space. We finished an initial phase where we showed that space-based remote sensing carries useful information. We’re now converting our research methods into a forecast product.
My main undertaking is leading a team that’s developing advanced statistical methods to do ecological forecasting, starting with the world’s coral reefs. We’re taking multiple observational data sets and an ensemble of global climate models that can predict things like sea temperatures over the rest of the century. We feed them into a Bayesian model to create high-resolution—and hopefully more accurate—projections of coral bleaching and mortality, with the goal of identifying those reefs that might hold out a bit longer from global stressors. This could help guide local conservation efforts. If we’re successful, we’ll see if we can apply our methods to other ecosystems and species, including humans.
PT: What has it been like to see climate change front and center in the news with the worldwide climate strikes?
KALMUS: It feels absolutely wonderful. We’re finally starting to see it get attention from the public, and that’s what’s needed to get meaningful attention from policymakers. For all these years, Earth scientists have held this knowledge and we’ve been kind of freaking out in our own peer-reviewed way. To have the whole thing largely ignored by the public and by policymakers was really hard.
I think the 2018 IPCC [Intergovernmental Panel on Climate Change] special report about 1.5 degrees Celsius of global heating was a game changer. It showed the kind of damage we’ll likely see at 1.5 degrees of global heating versus the far worse damage at 2 degrees. It laid out a very clear path: To have even a fighting chance to keep things at 1.5 degrees, we need to get halfway down to zero [emissions] by 2030 and all the way down by 2050 or sooner. For decades the public had been getting the lukewarm message “We’d better start doing something in the next five years.” The report made it really clear that, holy crap, we have to turn the ship around on a dime now.

At the same time, we’ve seen hurricanes and wildfires and floods and other climate-related catastrophes becoming more frequent and/or more intense. And then we have a new generation of activists like Greta Thunberg who are genuinely terrified and have been remarkably effective at communicating how serious this is. We’ve got presidential candidates writing climate plans that climate activists would have only dreamed about just a year ago, plans that could actually take us where we need to go in time to save global civilization as we know it.
So it’s just been a remarkable 12 months. I’m excited to see what happens over the next year as we head into the 2020 election. I feel like the grassroots climate movement is just getting started.
PT: You changed not only your research field as a result of your climate revelation, but also the way you were living your day-to-day life. When you talk about how you cut back on your personal fossil fuel usage, what do you think is the change that surprises the most people or makes people feel the most resistant?
KALMUS: Burning fossil fuels and generating CO2 started to feel less and less okay to me on a personal level. So around 2010 I started thinking, “If I wanted to burn less, how would I do that?” I sat down and figured out how much of my fossil fuel use was coming from driving and what I’m eating and so forth.
My biggest surprise was that most of my emissions were from flying. I had been thinking about putting up solar panels, but it turned out that electricity was pretty low down on my list of emissions sources. Flying was very, very clearly at the top. So I decided I had to start flying less.
When I give talks to the public about the science and about my response to the science, I always talk about flying. That’s a controversial topic even among climate activists and environmentalists. People can be pretty attached to their flying habits. For example, I talked to a woman who was a nurse; she would fly to Africa and help deliver kids there. It was a very worthy thing that she was doing, and it was a big part of her identity to go and help underserved women in Africa. But she was also concerned about climate breakdown and felt this deep conflict at the core of her identity. That’s not that uncommon. But unfortunately, physics is brutally honest about greenhouse-gas emissions.
And academics love flying to conferences—it’s a key part of our careers and how we think about academic productivity. So how can we collaborate without flying? Maybe through virtual reality conferences, maybe online conferences, maybe conferences with regional hubs connected together by remote technology? That’s the kind of thing that could also increase participation from Earth scientists in the Global South because it would cost a lot less to attend. Those scientists are especially important because there’s a lot of rapid change occurring in the tropics.
PT: You’ve talked about the importance of engaging politically and joining climate action groups. What groups do you think are doing really good work?
KALMUS: The groups I am active with are sort of on a scale from lowest to highest personal risk—because activism can carry social, career, legal, or even safety risks. Starting with the lowest risk, Citizens’ Climate Lobby is a group I’ve been in for almost a decade now. They push for a particular policy called Carbon Fee and Dividend, which would make all fossil fuels get progressively more expensive year after year. This would help drive change at all scales and across all economic sectors, and it would do so in an equitable way by returning revenues back to the people, so you don’t get backlash like the Yellow Vest protests in France.
In the US we have the Sunrise Movement—they kind of discourage people over 35 from joining, which I find a little problematic, but they’ve still been doing incredible work at directly pressuring politicians to support a massive climate mobilization in the form of a Green New Deal, which I feel is the scale of response that we need. This could include a carbon fee, but it goes much further and requires, for example, a moratorium on new fossil-fuel infrastructure and an end to fossil-fuel subsidies. Then Fridays for Future is a global movement of strikers, many of them schoolkids. Both of my kids have been active in this, and I’ve been a sort of scientific adviser. The idea is simple: Every Friday, take some time out to strike for climate.
The highest level of risk is Extinction Rebellion. Not all climate activists are willing to risk arrest, but more and more of them are. The thinking there is that working within the system for the last 30 years and trying to change it from within hasn’t worked, so it’s time to actually start disrupting that system with nonviolent civil disobedience. I think they’re right.
PT: What are you working on right now outside of your scientific research?
KALMUS: My main project is my second book, which is aimed at young people. I also have a project called No Fly Climate Sci, which is about advancing the flying-less movement, and I’m working on an app that will help people reduce their emissions and encourage them to beat the IPCC recommendation. Everything I do is geared toward shifting the culture.