Peter Kalmus

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Once I turned onto Peter Kalmus’ street, it was easy to spot his home. With waist-high arugula and white sage instead of a suburban lawn, some would call his front yard an overgrown mess. However, anyone trying to cut his carbon emissions to one tenth, eat a local vegetarian diet, and promote a healthy ecosystem would call the yard a great success.

Kalmus is an Earth scientist at the Jet Propulsion Laboratory/Caltech, in Pasadena, California, who decided a few years ago to try to cut his greenhouse gas emissions dramatically. By ceasing to fly, cycling as much as possible, and changing his diet (among other things) he’s now responsible for 2 tons of emissions each year; the American average is about 20 tons1 each year.

I had the pleasure of visiting Kalmus in his home in Altadena, a suburb of LA at the base of the San Gabriel Mountains, to talk about his lifestyle, his work, and the surprising joys of using less energy. We settled into conversation under his giant avocado tree (yes, I got to keep a few) after we made some hand-cranked ground coffee (yes, I too thought it was heavy-handed but it was also delicious).

The interview below has been condensed.

If you could design a course for first-year university students that had to deal with manmade climate change, what would it look like?

I would call it “The Anthropocene, or Our Ecological Predicament” —what does it mean to be a human right now? I am really interested in what I can do as one person, and there are almost 7.5 billion people right now. So what can one person do given this huge global predicament? It seems we don’t have the power to do anything about it as an individual. So how can we respond to that in a way that’s both effective and allows us to be as happy as we can be given all this depressing stuff.

And your classes?

Class One: What we know and what we don’t know

How hot will it be in 2050 and 2150? What are the certainties for those, because those are predictions? How long will the CO2 stay in the atmosphere? When will it come out? And then: when will biodiversity recover, because we are in the sixth mass extinction right now and a major driver of that is global warming?

Class Two: The science behind meditation and how meditation affects the brain

Not actually giving students directions to meditate, but letting them know how it works. I’ve been meditating for a very long time, and it’s totally non-religious. So anyone can practice. That’s one of the things I really like about it. In the West, we tend to look out so much—we’re looking at our gadgets, we’re emailing people, we’re watching TV—it’s all this external activity. It seems that we are terrified to stop and be still. So maybe after the third class, we would take some time to focus on the breath. And students would see that it’s really hard to do after 5 or 10 seconds, the brain starts to wander away…so it sounds so easy but it’s so hard. And for some people I think it can be a terrifying thing. I think it’s a really important response to this predicament that we are in.

Class Three: Composting

Something that is important to me is composting—I call it aggressive composting or composting everything. Every scrap of organic waste I generate. This could be a challenging one for a lot of the students. When I say everything, I mean everything.2

So the first three classes deal with science, our inner lives, and concrete practical action: three important kinds of truth. We need all three right now.

Class Four: TV screens and the physiology of addiction

So I’d have to do some research, but I think iPhones are physically addicting. In this country and other countries it’s outstanding how much time people spend in front of a screen3, and what does that do to our ability to interact with each other and have conversations with one another? What does having this constant barrage of advertisement do to our worldview? Does it make us more dependent on corporations? Does it blind us to other ways we can see this world? There’s no global warming in these ads. There’s no serious economic inequality in these ads. People are smiling and they just have this one little problem that gets solved by some product, and then their lives are perfect. It’s interesting to think about that ad culture.

Class Five: Techno-optimism and the myth of progress

We think science and technology can solve any problem that comes our way. I think with global warming and the psychological predicament, it’s possible that the majority of people think that we’re gonna solve this with technology. That we are going to throw more technology at these problems and solve it that way. There’s a sense that this techno-optimism allows people to not have to change themselves. To rescind their responsibility from this. “They” will save us. Who are these “they”?

Class Six: Global warming policy

I’d definitely want to examine a revenue-neutral carbon fee that I think is probably the best policy step we can make as a nation and consortium of nations. Any time coal comes out of the ground, oil, or fossil fuel comes into port—there’d be a tax on that depending on how much CO2 or methane is produced from processing and burning it. This fee would increase over time. So any product that needed fossil fuel to get made, certainly gasoline, natural gas, plastic, even food products that are fossil fuel intensive—all of these would get more expensive, over time. So there’d be a market based incentive both for corporations and individuals to find alternatives.

Which is different from a carbon tax?

Yes, a tax means that the government keeps the money, and a fee means the money goes back to the people. So households would get money back each year. And if you’re doing everything you can [to avoid using fossil fuels] you are saving money, and that’s money that can be spent.

Class Seven: How we are trapped by the need for economic growth

Politicians are all about growth. And the way that our system is set up if we don’t have that four percent growth, things get really bleak. Economists will say that we can keep growing forever, and they have theories of how we can decouple growth from fossil fuels. I have yet to be convinced of that. It just seems our whole system is based on fossil fuels.

That implies we need to shrink to some kind of steady state economy. I think it would have to depend on other things to pull it off. We’d have to figure out how to stop growing our population. The second thing we’d have to do is switch from a profit-based system to a benefit-based system. For a lot of humans, what gives their lives meaning is to amass as much wealth as possible, hoarding as much as possible, and making these bank accounts that can be passed on to children. The difference between the richest few people and the average person is such a wide gulf. It’s just not clear what one individual needs ten billion dollars for.

When the money grows, the ego grows with it; people become slaves to the money they hoard, and it disconnects you from other people. There’s a segmentation of society, and this ties into meditation too because there’s a certain fundamental form of suffering that we don’t talk about—wanting. If you want something it implies that you aren’t happy with what you have in that moment, that somehow you feel incomplete.

Class Eight: How to live with one tenth of the fossil fuel

Four or five years ago, I realized I had been worried about global warming for a very long time but I hadn’t changed anything about myself. I’d be running around saying “We’ve got to do something about this,” and “Why isn’t anyone doing anything about this?” and realized that I hadn’t done anything myself. So I sat down and thought—I drive, I eat foods, I fly on airplanes, I use natural gas and electricity, and so forth…how much greenhouse emissions are emitted each year I do those things?

It took some research but I figured it out and I basically made a pie chart. 75% of my emissions in 2010 were for flying. At that time I was still doing astrophysics and I was a post-doc. You’re trying to become a professor so you fly to give talks at conferences and various meetings, and so I started to realize, whoa, 75% of my emissions, and I’ve got these little kids. They’re going to say, when they’re grown up and say global warming is really bad and we didn’t mitigate—it’s really hot everywhere, the weather is crazy, there are mass extinctions, agriculture is strained, there’s sea level rise and migration away from coastal cities, and all of this bad stuff we hear about—what if that happened and its 2050?—and my kids say “Dad, it’s bad, why didn’t you do anything?” And that’s when I started to think of global warming as more of a moral issue.

We know enough to say that burning fossil fuels causes harm. On a time scale of humans, it’s essentially permanent harm. It harms humans, it harms people who haven’t been born yet, it harms people living on the other side of the world, people living in Kenya. No one can escape it. And it hurts nonhumans as well. So I can’t avoid the implication that we have a moral reason to not burn this stuff anymore. We have to stop burning it.

I started biking more. Biking was the first thing I started doing. It was an eye opening experience for me. I felt 20 years younger and alive. It was fun. I started growing some food—I think it’s just a miracle that food grows on trees.

The point I’m trying to make is that I started doing all these things to move away from fossil fuels and lo and behold I liked these changes and they made me happier. So I kept doing them. And I saved money, too. I started experimenting with veganism and composting, and now I emit less than one tenth of what I emitted in 2010. It’s actually pretty easy to reduce down to about a ton or two per year, but given how our society is set up, it gets harder to go past that.

Chickens in the yard at the Kalmus residence in Altadena, CA.
Chickens in the yard at the Kalmus residence in Altadena, CA.

There’s so much greenhouse gas going in the air so that reducing my emissions from 20 tons per year to nearly zero isn’t enough to have any impact. Which you could think of as really depressing. But there are a few reasons why I think it’s really good. I just like it better—but the other really big reason it’s worth it to me to make these changes is because it starts to tell a new story. It tells people that it’s possible to live with a lot less fossil fuels and it’s not bleak. People assume you have to make all these sacrifices, but that’s not quite right. You have to change, and you gain things. 

The third thing is there’s something really important in this life about aligning our actions with our core principles. I think that misalignment leads to unhappiness. It just eats away at the back of your mind that you’re doing stuff that goes against the grain of your beliefs. And if you change your own actions it doesn’t magically make everything around you better, but it’s just nicer to fix that cognitive dissonance.

I don’t want anyone to feel guilty. There’s way too much guilt in environmentalism right now, and I don’t think it’s helping us make change. When someone is feeling guilty, there’s this unpleasant sensation. So they just want this unpleasant sensation to go away. They aren’t really looking to live in a sustainable way, they’re just looking to move away from feeling guilty. So in the 90s it was all about recycling. Recycling was the thing you could do to not feel guilty. Then you could get in these planes and emit all these fossil fuels and life was good because you were doing that talismanic thing. Guilt leads to superficial changes and prevents deeper awareness.

Class Nine: The shortcomings of mainstream environmentalism

What does the term “green” mean? No one has actually sat down to define that, and corporations have co-opted it. So much of mainstream environmentalism is about guilt; it’s about fear.

What we need is a new environmentalism…even the word environmentalism implies a duality between the human world and the natural world, so there’s this duality between economics and jobs which always comes up every time environmentalism comes up. I’m looking for something new which is more about: how can humanity live in a way that’s aligned with the biosphere?

Class Ten: Exponential growth

The human brain isn’t very good at understanding the exponential function. Global warming feels like it’s accelerating to me—and maybe that’s just our awareness. But there’s been this exponential growth in our emissions and exponential growth, the famous hockey stick in the air, as we recently reached 400 parts per million, so that was growing exponentially until recently. Each day we are making more humans than we’ve ever made in the past. I’d like to explore these trends in resource usages and trends in global warming—are they actually exponential? What does that mean mathematically? What does that mean in terms of doubling? Are there already too many humans on the planet?

Class Eleven: Humans and nonhumans

I think there’s a trend in the humanities that part of the predicament is speciesism: we put humans above all other types of species. We see ourselves as special and we see it as our duty to conquer everyone. Should animals have legal rights? There’s a lot more science being done that addresses this question. I think scientists are starting to recognize that animals have emotions that are quite similar to our own. They have friends, they can experience love for their offspring, they can experience love for their mates. I think for a long time doing this kind of science was kind of taboo, but I think it’s changing. [Carl Safina’s book “What Animals Think and Feel” explores this question — Ed]

We can also talk about some things that have been beaten to death, like factory farms. I think a lot of people buy meat in shrink wrap packages and they aren’t really aware it came from a living being. There’s also a disturbing trend in diseases—viruses and bacterias. When you keep animals in bad conditions, viruses can evolve rapidly and we’re seeing new viruses.

Class Twelve: Limits to academia

There are things you can’t teach in a classroom. Gardening, raising chickens. Maybe living without fossil fuels. I like living with one-tenth the fossil fuels, but until people actually go out and try it, I don’t think they’ll believe me. So there’s really a limit to how knowledge can be transferred. 

And global warming is by it’s nature extremely trans-disciplinary. It doesn’t fit neatly into any one of our current academic disciplines.

Class Thirteen: Economics of corporatocracy

Money in politics paralyzes government and blocks action on issues like global warming. And the for-profit worldview doesn’t really work in a future steady-state economy. We need to get money out of politics. 

Class Fourteen: Envisioning a truly sustainable humanity

A sustainable humanity is a humanity that is happy living in the moment, doesn’t want a lot of things it doesn’t have, doesn’t see shopping as a way of happiness; maybe it’s a utopian future where there’s no war anymore, and people place others’ needs before their own.

You cite owning land in Altadena as one of the reasons you were able to fully connect with the idea of “be-cycling,” a deeper approach to sustainable living. As most of the country (and soon the world) is urban—how can we translate the power of growing one’s own food into something that urban communities can both see, feel, and do?

For one thing—community gardens. There is a community garden here in Altadena and I’ve been on the waiting list for five years. I finally got a plot.

I think there should be ten times as many community gardens. I think all the vacant lots should be turned into gardens. I think there should be municipal programs that convert land into community gardens. I think there should be policies that favor low income and apartment dwellers to get first dibs on community garden plots. I’d love to see an end to lack of supply. There should not be anyone who wants to garden and is unable to garden. 

The worst parts of myself keep saying: well, he has a career, he has a family, he owns a house in the beautiful suburbs—he is in the perfect position to undertake this. I want to travel the world and road trip and eat whatever I want, and then I’ll settle down. What would you say to that?

That really ties into the moral part. You can’t stop burning fossil fuels cold turkey. So there has to be some slack time and you have to do what you can. It’s such a hard question. I’ve been thinking about the morality part because it’s not only about not burning fossil fuels, but about doing everything you can to move away from that system. But it seems unsatisfying to say that. It seems like a cop out. But it took me a long time, many years, to get to this point. And I only reduced by a factor of one tenth. I do have a lot of privilege. I was fortunate in my career that I was able to move from Caltech to JPL, which I just happen to live a few miles away from.

Everything I do saves me money. So there are people who go about this a different way—buy solar panels and electric cars and such. And that’s a privilege. But the way I’ve gone about it is a way that everyone can go about it.

All I can talk about is my experience. Everyone is going to have his or her own path. Flying is the toughest. If you fly more than 10,000 miles a year, chances are very good that flying will be your largest source of emissions.

What we want now out of travel experiences are cheap, convenient and fast trips. Instead, we could substitute other values, such as adventure and greater depth of travel experience. I think a lot of people would sign up for ocean travel if we had more vacation days. 

Italian workers have four weeks of paid vacation, by law, and ten additional paid holidays, and when you tell them about the US, they can’t believe it. We put profit too high up. We are willing to run in this rat race with no vacation time, barely any maternal or paternal leave, we put our kids in daycare…the whole system is interconnected and it needs to change.

We need to make a world that’s fun to live in and good for humans—not good for corporations. There’s nothing wrong with being successful but we need to redefine success. We have to rethink productivity and what corporations are for—are they to amass as much wealth in one place as possible and rule the world? Or are corporations there to help us live happier lives?

What do you miss from your old life?

Let me reframe that: what would I keep doing if global warming suddenly disappeared? I’d keep biking—I love biking. I’d keep gardening. I’d keep having chickens. I’d keep having bees. I’d keep doing science. I might eventually go back to astrophysics, at least part time. I used to search for gravitational waves, and I also used to enjoy thinking about cosmology. I ended up becoming an Earth scientist because I couldn’t stop thinking about global warming so I had to study it full time.

I’d probably fly from time to time. But that one I’d have to think about because I have gained a lot by giving up flying. One of the things that was really surprising about giving up flying is that I think my relationship with my parents is closer now [because our time is more precious together].

What will it take to convince people of human made climate change?

If I could answer that we’d probably not have global warming right now. But I think the way things are going to go the effects of climate change are going to be more and more severe and start affecting more and more people directly and then people will have friends or relatives who are directly affected. So once people feel it directly and start having economic losses and even losses of life or knowing people who that’s happened to then they will quickly believe it and demand that politicians do something.

But then again, George Marshall claims that it’s actually the opposite, that when people experience climate-related disasters they’re actually less likely to believe in global warming.4 They get caught up in the immediacy of rebuilding, and they need to pretend that the disaster was a one-time thing, not part of a global, increasing trend, something that might happen in the future with increasing frequency.

So maybe what it will take will be a lot of us telling this new story through how we live, and gradually shifting the culture.

Do you think it’ll be too late?

In some senses, it’s already too late. The thing about global warming is that it’s not an on-or-off thing. It’s a ‘how bad is it ultimately going to get’ sort of thing. No matter how quickly we ramp down our emissions, it’s going to be bad. If we wait another 10 years to ramp down our emissions it’s probably going to be pretty awful. If we wait twenty years, it’s going to be truly horrendous.

You have two kids—ever feel bad for them?

It’s not clear to me that I’d be doing all this if I didn’t have kids.

When my kids were born, it was a big kick out of my own selfishness. You can’t put into words how having kids, some bell goes off in your head, and everything changes. I went through this process of grieving about global warming and this ecological predicament and all of this stuff that we’re losing, in my opinion, needlessly. After going through that process of grieving, that’s when I went into overdrive and thought I can do nothing and feel terrible about this or I can do everything I can possibly do which might not be enough but at least it’s everything I can possibly do. But frankly, yes, it’s a little bit frightening to me the world they might grow up in. I don’t know what it’s going to look like.


During our three-hour chat, I was surprised by how Kalmus could deliver such dramatic news about our planet with an air of serenity. I suppose it has to do with his moral alignment, his meditation practice, and his endless supply of avocados.

By the end of our talk, Kalmus was late to pick up his kids. So he put on his helmet, grabbed his bike, and rode off into the Altadena sunset.

Peter Kalmus received both his undergraduate degree, from Harvard, and doctorate, from Columbia, in physics. His personal website is; his opinions are his own, and not necessarily those of NASA, the Jet Propulsion Laboratory, or Caltech. An article he wrote about his decision to stop flying is in Yes Magazine, and his forthcoming book, Being the Change: Live Well and Spark a Climate Revolution, will be released by New Society Publishers in spring 2017. 

Interview and photographs by Alice Goldsmith


1 – Per capita emissions are measured both for CO2 and for greenhouse gases collectively (methane and other gases also contribute to global warming). A Google search for ‘per capita emissions’ often returns the CO2 measurement, but the total GHG measurement will be higher; for 2012, the US per capita GHG estimate is 19.98 tons, per the Emissions Database for Global Atmospheric Research.

In addition, US states vary widely, and individual and household emissions are often a function of wealth matched with lifestyle; affluent suburbs in the US tend to have the largest household carbon footprints. The Cool Climate project at UC Berkeley created an interactive map of the United States showing household emissions by Zip Code, as well as a more detailed emissions map for the Bay Area. The Cool Climate maps attempt to factor in embodied emissions from products made overseas, as well as travel.

Peter Kalmus adds: “The truth is that we probably only know a per capita measurement to within a few tons, probably in the range of 17-23 tons after including international shipping, air travel, and offshoring of manufactured products.” As an example of ‘offshoring emissions,’ our computers and phones are typically made in China, and the emissions from their manufacture are counted on the Chinese side, though the products end up in the US.

2 – Kalmus composts everything organic, except paper and fabric. “Paper gets recycled, fabric donated or turned into rags and eventually thrown in the landfill. I tried composting cotton fabric but it just goes too slowly.”

3 – Regarding addiction, mobile devices, and social media: “We Are Hopelessly Hooked”, Jacob Weisberg, The New York Review of Books, 2/25/16; “They’ve Got You, Wherever You are”, Jacob Weisberg, The New York Review of Books, 10/27/16. Political polarization can become inherent in a social media business plan. See: “Facebook’s Attack on Democracy”, Quentin Hardy, The New York Times, 8/26/16; “Hyperpartisan Facebook pages…”, Craig Silverman, BuzzFeed News, 10/20/16.  In contrast, open governance on a site can make the content more accurate, and less polarizing. See: “Wikipedia is fixing one of the internet’s biggest flaws”, Jeff Guo, Washington Post, 10/25/16

4 – George Marshall “Why Our Brains are Wired to Ignore Climate Change,”  reviewed in Washington Post, 8/21/14