🌌👩‍🌾 Terraforming Mars: A Quick Q&A with … Edwin Kite and Robin Wordsworth on designing a new home beyond Earth

'Restoring a habitable planet is harder than sustaining one, so terraforming can be viewed as the ultimate sustainability challenge.'

My fellow pro-growth/progress/abundance Up Wingers,

As the prospect of human settlements on Mars draws closer to reality than we could have realistically imagined pre-SpaceX, so does the concept of terraforming, or shaping alien landscapes beyond Earth to suit human needs. The idea of an interplanetary species was first conceived in the 1890s. Not so long after, the idea of modifying the topography and natural resources of planets and asteroids arose as early as the 1940s, before being picked up by imaginative writers like Carl Sagan and Isaac Asimov. The above image depicts the first day of blue skies on a terraformed Mars in the 1990 film Total Recall.

In their recent article for Asterisk magazine, “Greening the Solar System,” Edwin Kite and Robin Wordsworth discuss what it might actually look like to transform Mars from hostile desert to verdant human habitat. From their paper:

The possibilities for how we might do this range widely, from terraforming Mars (and possibly other planets or moons) to generating habitable bubbles on free-floating asteroids. While technological challenges remain, many of these techniques appear surprisingly feasible — making a detailed assessment of their merits all the more important.

I asked Kite and Wordsworth a few quick questions about how we might go about this ambitious project and what the implications might be for the environment, the international community, and more.

Kite is an associate professor in the University of Chicago’s Department of Geophysical Sciences, where his research focuses on planetary science. He is also a resident of the Astera Institute.

Wordsworth is a professor of environmental science and engineering, as well as of earth and planetary sciences at Harvard University. His research areas include climate evolution and the habitability of planets. He also oversees Wordsworth Group, a team of planetary scientists researching climate and habitability.

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1/ What is the value of terraforming other planets?

As far as we know, our Earth is the only planet with sunlit oceans and an atmosphere we can breathe. Proposed motivations for terraforming are diverse. For any level of technology, two worlds have more carrying capacity than one, so terraforming allows us to expand our numbers. For some, terraforming offers some protection for our biosphere and human consciousness against existential threats. And, as we move out into the Galaxy, we will need base-camps, and a base-camp on the scale of the Galaxy is a habitable world. An overarching challenge for changing the environment of worlds beyond Earth is how to compress the planetary development that has made at least one world habitable to us, but took billions of years, and accelerate it to timescales relevant to us. Restoring a habitable planet is harder than sustaining one, so terraforming can be viewed as the ultimate sustainability challenge.

2/ How much traction is the idea of greening the solar system gaining?

We think most people would prefer a living universe to one that's almost entirely dead. The question is whether the costs (including the need to check for existing life) outweigh those benefits. The research community on the topic is small but growing, with a recent Mars terraforming workshop in Pasadena and another planned. NASA's former Chief Scientist, Jim Green, has advocated for Mars terraforming.

Local terraforming, for example tiling the surface of a patch of Mars or of an asteroid with warming membranes, could happen on the timescale of months. . . Much more time, at least centuries, would be required to build up oxygen levels throughout a planet's atmosphere.

3/ What would the timing and scale of such a greening project look like, realistically?

Local terraforming, for example tiling the surface of a patch of Mars or of an asteroid with warming membranes, could happen on the timescale of months. Warming Mars with the intention of allowing simple forms of life might be relatively rapid, potentially within years. However, temperature is just one part of surface climate, and pioneer forms of life within Mars soil would face many challenges beyond just climate. Much more time, at least centuries, would be required to build up oxygen levels throughout a planet's atmosphere. Altering the climates of Titan (currently too cold for life as we know it) or of Venus (currently too hot) would also take centuries. Humans have already altered the orbit of a volatile-bearing asteroid — the successful Double Asteroid Redirection Test in 2023 — but the objects that carry enough volatiles to irrigate an entire planet are much larger. Moving such volatile-rich objects around the Solar System — which would be necessary to terraform Earth's Moon or to irrigate a cooled Venus — would necessitate propulsion technology that humans have not yet achieved.