Terraforming, the idea of creating sustainable habitats and biospheres beyond Earth, isn’t just science fiction. Edwin Kite, associate professor in geophysical sciences, is one of many scientists studying how humans might live on Mars. In May he coauthored a piece in Nature Astronomy, “The Case for Mars Terraforming Research,” proposing that rigorous study of Mars’s physical, biological, and chemical conditions is necessary before making decisions about inhabiting the planet. Such research, Kite says, could also contribute foundational knowledge about our universe: “By studying climate change on Mars, we learn a lot about processes that matter for climate in general.” This interview has been edited and condensed.

What are some possible choices for the future of Mars?

One is that people never visit. But I don’t think that’s likely. Many countries have contributed to Mars exploration—there have been missions from India, China, Russia, the United Arab Emirates, Europe, the United States. A lot of this investment is driven by the idea that humans will eventually go.

One model is the Antarctica model, where we send all the supplies people need from Earth to Mars—expensive camping trips. If we cut off supplies, the people there will be in trouble pretty quick. That’s not really sustainable.

Another model is local or regional terraforming. You might create a local habitat—a dome, for example—and within that environment you might have ponds, lakes, and forests, and you’re producing most of what you need from the soil, air, and rocks on Mars. 

The third model is global terraforming, which is when the whole planet becomes habitable. People have looked at this for about 50 years. There are NASA studies from the mid-1970s; Carl Sagan [AB’54, SM’55, SM’56, PhD’60] wrote papers on this. If you want to do this, there are two steps. There’s a relatively quick and easy step of warming up the planet to allow photosynthetic life, and then there’s a hard and slow step of building up the oxygen levels, allowing more complex forms of life.

Why does Mars terraforming interest you?

The research is going to be an effort that will span many generations, like space exploration itself. So we can start work now that will pay off later, and a good starting point is to think about the basic physics and chemistry and how those will constrain our choices. Some of that information we’ll get from the rovers and orbiters that are already on Mars. Some of it will require more experiments, calculations, and simulations on Earth. And some of it will probably require additional missions to gather data that will allow us to make an informed choice about the future of Mars.

Our political attitudes toward pretty much everything change on timescales of just a few decades. What’s not going to change is the science, so that’s a natural thing to focus on.

In the Nature Astronomy piece, you mention that interest in terraforming research was high in the ’90s, declined in the 2000s, and is now on the rise again. What explains this ebb and flow? 

The Mars Exploration Program has given us lots of knowledge we didn’t have 20 years ago, so some of the discussion then about what was possible was just wrong. In the ’90s there was a lot of excitement about the idea that you could relatively easily warm Mars by releasing carbon dioxide from the south polar ice cap. In the 2000s and 2010s, we learned there isn’t that much carbon dioxide in the south polar ice cap. 

In terms of why people are excited again, I think it’s the falling cost of access to space.

Do you think climate change on Earth has increased interest in Mars terraforming?

No. Making Mars’s surface habitable for humans to walk around unaided would take at least centuries. Mars is not a solution to our societal-scale problems on Earth—in part because we tend to take those problems with us. Mars is not Plan B for humanity.

So if humans moving out into space in large numbers is not a backup plan, then why do it? I think curiosity is a big driver. As we move out into the universe, we’re going to need base camps. As we move out farther and farther, we’re going to need to bring our life- support systems with us, and our largest-scale and most important life-support system is the biosphere.

You’ve written that it’s important to consider the ethical and scientific aspects of terraforming in tandem. Why?

This is how consensus is formed for any new technology. For example, biotech is constantly creating new possibilities that raise serious ethical and philosophical questions, and ultimately the discussion leads to a consensus that leads to societal agreement that gets codified into law. Gene therapy and organ transplantation aren’t considered controversial now but were once highly controversial. And sometimes, informed by research, we decide collectively not to move forward with a technology. How can we know in advance what will happen?

We have treaties about the use of outer space; one from 1967 says the exploration and use of Mars “shall be carried out for the benefit and in the interests of all countries, irrespective of their degree of economic or scientific development, and shall be the province of all mankind.” These agreements constrain large-scale actions.

And we have, as humans, reached consensus about lots of stuff like that. The Montreal Protocol protecting the ozone layer is one example. The deep-sea floor is another example: There’s an organization called the International Seabed Authority that has jurisdiction over economic activity on the deep-sea floor. Antarctica is another example.

What is your favorite piece of Mars-related pop culture?

I’m fond of The Martian. I think it captures the rhythm of space exploration really well. I’m a participating scientist on the Mars Curiosity rover. In The Martian, even though it’s a story about one person stranded on Mars, a lot of the drama is about the team back on Earth figuring out how to get him out of the problem. I think it captures the teamwork well. And the fictional hero of The Martian, Mark Watney, is a University of Chicago alum.