In Trouble with Terraforming Mars, I looked at many things that could go wrong with such a project. But setting aside those issues, Mars terraforming takes us far into the realm of magical thinking - where if you can imagine something vividly, you can make it happen. 

In this imagined future, with the ability to use giant space mirrors to warm up Mars, it is also easy to solve the energy crisis on Earth - just beam all the energy we need back to Earth from space solar power stations. With the fine control we need over planetary atmospheres, it is a trivial matter to adjust levels of CO2 from 0.04% back to 0.03% and stop global warming instantly.

Who knows what else we can do? We surely have fusion power by then, and with such vast powers we can probably also construct habitats anywhere in the solar system, including the Oort cloud, and the atmosphere of Saturn. Would we still want to terraform Mars? Would we be grateful to pioneers who attempted to terraform the planet a few decades or centuries previously? Or would we shake our heads in dismay at the way they have messed up the planet and made things hard for us?

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Who knows, perhaps those vivid future imaginings will become a reality some time in the future. But there again, it might not happen. There might be many things about that picture that we are unable to imagine clearly and accurately right now.

What's easy to forget is that science fiction writers don't always get things right. They imagined television long before its time, but also wrote stories with explorers using slide rules in spaceships that travel faster than light. (Full text of the book, "Islands in Space" by John Campbell). The hard science fiction writer Isaac Asimov got many things wrong including his Multivac, a vast multi-story, half a mile long supercomputer made of vacuum tubes, with only one computer in the world.

 Detail of the back of a panel of ENIAC, showing vacuum tubes. This was taken from the computer lab, which has a glass window to the back of the piece of ENIAC on display at the Moore School of Engineering and Applied Science. The image was perspective-corrected and cropped by myself. Original photo courtesy of Paul W Shaffer, released under GNU license along with 3 other images in an email to me. Copyright 2005 Paul W Shaffer, University of Pennsylvania.
Back of one of the panels of ENIAC. In his early stories, Asimov imagined that by now we would have a huge supercomputer several stories high and a half a mile long built of vacuum tubes like these - or in another story - that it would be the size of Washington DC - with many interior corridor, with the one supercomputer serving the entire world, or an entire country. 

All the famous hard science fiction writers have had epic fails like this, as well as, sometimes, astonishingly accurate predictions.

There are many epic fails of science fiction like that (I mention a few more in Trouble with Terraforming Mars), as well as many astonishing moments of foresight.

The same is true of future technology predictions. If you look at "tomorrow's world" type predictions from a few decades ago, you get the same mix of things that turned out exactly as described, or even, before they were expected, and things that remain far into the realm of future fantasy to this day.

It is fine to use these ideas for inspiration, to stimulate the imagination and encourage "out of the box thinking". But they are far from ideal as guides for practical long term engineering decisions.

Usually I put a question mark into the titles of these articles. But this time I'm not sure it needs a question mark. What do you think? (I do expect what I say here to be controversial).


You might think this doesn't matter, as no-one has plans to terraform Mars right now. But the thing is, the background motivation behind our current ideas for Mars colonization is to terraform Mars eventually to make it habitable for humans. And that idea has a powerful hold on our imagination.

NASA's current manned and unmanned space program for the next decade, and its motivation for forward thinking for the next twenty years also, is largely based around the idea that some day we will want to colonize Mars. They do not have a worked out plan to do this, but repeatedly motivate Mars missions with the idea that it is one more step on the way towards eventually colonizing Mars. The private company Mars One is entirely based on this idea and Elon Musk with his Space X Mars colonization plan is also a powerful force in favour of it.

If this idea is an unrealistic one and an example of magical thinking, then it is taking up a huge amount of our current thinking and planning and space budgets. If you look at the hard figures, Mars is not an appealing place to go to as a place to live. It is far better, and cheaper to colonize the deserts on Earth with, for instance, seawater greenhouses.

Sundrop farms greenhouses

If your motivation is to find new places to live in the solar system, it would cost far less, and be more useful for the Earth also, to build your colonies on Earth. These seawater greenhouses are perhaps closest to Mars ideas, of using in situ resources to grow things in a self enclosed habitat. But of course here on Earth we have abundant sunlight in places like Australia, and seawater, and oxygen in the air, protection from cosmic radiation, and so on. For far less cost than a Martian colony, and with far more people benefited, we could build colonies living in seawater greenhouses in our deserts near the sea.

Also if your motivation is to find a safe place for humans in event of a disaster, then no likely scenario would make Earth anything like as inhospitable as Mars. For more about this, see If Mars Is For Hardy Explorers Only, Where Is The Best Place In The Solar System For First Time Colonists?

I think the powerful idea that Mars could be terraformed is what gives the planet its appeal, as a place people want to colonize. All agree that it is no second home at present, but there is this idea, maybe it can be transformed. And in science fiction this transformation often takes just a few centuries.

Most of us have read science fiction stories such as the Mars trilogy, or watched movies about astronauts on Mars, and imagine, vividly, that some day we might colonize and terraform Mars. It is natural then, to want to make that happen. But things you imagine vividly are not always things that you can make happen.

Cover for the third novel, Blue Mars, in Kim Stanley Robinson's trilogy.

Science fiction stories of the past are a mix of astonishing foresight and major epic fails.

Imaginative future novels like this one are great for out of the box thinking and to stimulate our imagination, or just fun, but they are not good guides for engineering decisions or actual practical colonization planning. 

Mars One have said that they have no plans to terraform Mars, and will keep to things that are known to be possible with current technology. Yet, I think their ideas would have far less appeal to the general public if we didn't have the idea in the back of our minds that somehow, some day, Mars could be made more habitable than it is now. 

Elon Musk of SpaceX, who hopes to send thousands of colonists to Mars eventually, has made it clear he thinks in terms of terraforming Mars eventually.

Interviewer: "Life is sustainable on Mars?"

Elon Musk: "Well you'd need to live in a dome, initially, but over time you could terraform Mars, to make it like Earth and eventually you could walk around outside without anything, on Mars. So it is a fixer upper of a planet"


First, let's look closely at what this is, and how it has pervaded thinking of mission planners to date. Many expensive and unnecessary projects have been started and then cancelled because of the human tendencies towards magical thinking. (This duplicates a section in my Will we build colonies that float over Venus like Cloud Nine?)

This is a trap we can all fall into. When you are keen on an idea, then you can ignore things that are problems with it - and often don't even know that you do it. This is not just an issue for amateur theorists. There was a great recent discussion on the space show recently, where the guests raised examples of magical thinking by NASA itself.

The Space Show Classroom with Drs. Jurist&Logan, Monday, 1-6-14

Examples include, the way NASA continued to use the space shuttle after the Challenger disaster. As with the earlier O-ring disaster the NASA managers got used to the foam block debris, during launch, although it was not supposed to happen according to the plans - the "normalization of deviance". This is not a scientifically valid approach. Something that works fine 20 times may fail on the 21st occasion, just through probability so you can't deduce from "it's okay so far" that it will continue to work fine. It is just human nature to tend to fall into these ways of thinking, and we see from experiences like this, that scientists can fall into these traps of magical thinking, in the same way that anyone else can. Eventually this lead to the Columbia disaster.

The space shuttle also cost many times more than the Saturn launcher per ton to orbit (though cheaper for return of mass to Earth). The ISS could have been built for a much lower cost using the Saturn launcher.

Space shuttle
Space shuttle launch. Though the program caught the imagination of politicians and space enthusiasts alike, and did lead to much new technology, arguably it's an example of magical thinking, as suggested in the show.

Those involved got caught up in the vivid idea behind it. But financially, it would have made more sense to continue to use the Saturn V launcher. The ISS would have cost far less to build with Saturn V.

Then after the Challenger disaster with the O-ring issues, the same kinds of management mistakes were repeated with the foam blocks leading to the Columbia disaster.

This may be an example of magical thinking.

They also cited the Constellation program - finally axed by Obama - as another example of magical thinking where the scientists involved simply hadn't done the proper sums which would have shown that it wasn't viable financially, in the view of the speakers on the space show anyway.

So, we have to be aware of this when discussing topics such as, Venus cloud colonies - or Terraforming. There may well be hidden issues that we don't notice or don't give enough prominence to in our thinking.

The best solution, mentioned on the show, is to surround yourself with people who are cleverer than yourself, who can correct your errors. But not to assume that they will always get things right just because they know so much, as we see from the NASA experience that clever people also are prone to magical thinking.

In the case of terraforming, it is especially easy to get drawn into the realms of magical thinking. I have that happen to me too, so know what it is like. For instance, I find find the Venus cloud colonies ideas so cool, with such interesting physics, that I find it easy to get caught up in my enthusiasm, and downplay or ignore the issues with sulfuric acid, or the difficulties involved in returning to Earth.

It's the same with terraforming. The ideas seem so good, and you can imagine them so vividly, and back of the envelope type calculations seem to work. It is all on such a grand scale anyway, planetary scale mirrors, seed factories covering an entire planet, timescales of centuries and millennia. Soon, you get to start thinking it really is possible, in the near future, with current technology. You imagine that future world so vividly, it is easy to forget the bottom line, the vast future costs involved, the vast timescales and the sizes of the things you imagine, and to forget how far advanced these ideas are over anything we could conceivably do right now. 

Also it is easy to ignore issues that would need to be addressed. Many niggly but important things such as a planets magnetic field, or axial tilt, or orbital eccentricity or distance from the sun, or the unpredictability of living organisms (with current knowledge), such as the ones I go into in Trouble with Terraforming Mars.

At the same time, there are projects that seem impossible but are actually just around the corner. It is hard to distinguish sometimes between these near future apparent impossibilities that actually get built a few years later, and magical ideas that truly are way beyond current technology or don't make any financial sense.


One of the most detailed versions of Mars terraforming is the one worked out by Zubrin for the Mars society. Here is how it goes, all summed up in a nice image, see How We Will Terraform Mars. It all looks great at first sight:Making Mars the New Earth

I'll just take a look at a couple of points in their plan.

First of all, they plan to start the process of terraforming by putting giant mirrors into orbit around Mars. These warm up the planet and also make it sunnier for photosynthesis. 

Constructed in high orbit above Mars, the mirrors would reflect sunlight back onto Martian surface. In McKay and Zubrin's model, the mirrors would not exactly orbit Mars.  Rather, they would reside directly above Mars' night side, held in place by a balance of forces between Mars' gravity and the solar slight pressure.  The orbital mirror plan has the advantage of continually introducing extra heat into the Martian climate long after the poles have sublimated.  Even in the later stages of terraforming, Mars' distance from the sun will make the increased insolation from the orbital mirrors desirable.

If you can send giant mirrors like this to Mars, as I said in the intro, then you already have the technology to solve our energy crisis on Earth. You can build solar energy satellites in orbit around Earth in the same way and beam the energy back to Earth.

If Earth doesn't take on this mega project of mirrors around Mars, do a small group of a few thousand Mars colonists (assuming it goes that far) have the capability to do it?

Robert Zubrin talks about a century of colonization on Mars to build up the industrial base needed to terraform it. After a century, if it does survive that long, maybe Mars could develop an industrial base of its own, with its own factories like the factories we have on Earth - though of course working with much more difficult conditions on Mars than on Earth.

But the thing is, it's not capability that you need, but spare capacity after doing all the other things you need to do to stay alive. Would the Martian colonists have the spare capacity to terraform their planet? When we on Earth with all our billions, and far easier conditions for building factories and machines, do not yet have the spare capacity to make small changes in the climate of Earth, at least not easily? 

Maybe they could, who knows, with 3D printers, and controlled von Neumann machines or seed factories and so on. But for us right now, this again is magical thinking. Should we make plans now on the assumption that, in that future a century from now, this is what they will be able to do, and will want to do? 

The plan here would be to introduce highly UV resistant lifeforms, such as lichen, directly on the surface or to grow cyanobacteria in soil which would protect the organisms from UV, and in mats on the newly formed seas, with layers of dead cells protecting the living cells beneath. These organisms would release oxygen which would slowly build to breathable levels and would form ozone in the upper atmosphere, which would reduce the harmful 190-300 nm UV flux. These organisms would also provide nutrients to help build the Martian soil up to the point where it could support more complex plants.

That sounds great, but how do you know that it would work out like that? There would be many other micro-organisms around from a human habitats on the surface (they plan to have humans on the surface from get go). Nature often behaves in unpredicted ways. Some unexpected microbe could out compete the cyanobacteria. They could get eaten, or all the oxygen is used up as quickly as it is produced. And the cyanobacteria itself can evolve and change its behaviour as it spreads over the planet.

And the idea that you could generate oxygen so quickly, - would it work like that, even in ideal circumstances?

Here is a slightly different perspective, from: Terraforming Mars: Experts Debate How, Why and Whether

James Kasting: "as Chris (McKay) already pointed out, the oxygen is a major problem. If you think about oxygen in the Earth's present atmosphere, you have to bury organic carbon. It's not enough just to have photosynthesis, you have to bury the organic carbon that you've produced. On Earth, we bury about one-tenth of 1 percent of primary productivity in the oceans, and that gives oxygen about a 4 million-year lifetime, meaning you have to do that for 4 million years."

"Now, if you're really optimistic, suppose you could get oceans going on Mars, and you had as much productivity as you had on the Earth. And let's say that instead of burying 0.1 percent you could figure out how to make that system bury 10 percent of the organic carbon. It would still take forty thousand years to build up oxygen. That's a daunting task which I hardly can envision us doing. "

"So that leaves us with terraforming it for plants, and, well, we can debate whether that's worth doing or not."

So, if it works, the timescale may be immense. Terraforming Mars for tens of thousands of years? We have only had a technological civilization for a couple of centuries, and had computers for less than a century. How can we start to think about taking on a project that will take tens of thousands of years to complete? Even one that takes the nine centuries of the Mars society plan would be far longer than any other technological megaproject, ever.

There are many other enthusiastic plans for colonizing Mars. You can find some good pages on the subject at the Red Colony website.

There are also many criticisms of the idea. See for instance, A New Earth - Not all scientific projects that will soon become feasible are also desirable. One example: terraforming on Mars.


The Daisy model gives a simple example of biological planetary regulation in action. It's a planet with just black and white daisies on it, which is able to keep the same surface temperature as its sun heats up, up to a certain point, when the process breaks down.

Actually a team of students in Valencia came up with a rather fun project to transform a planet such as Mars into a form of daisy world. Their idea is to engineer a microbe which changes colour, so it gets whiter as the planet warms up, so keeping the temperatures steady. For more about it, see Modeling Mad Yeast On Mars 

It's a nice idea, which is useful to show in a simple way what can go wrong with biology based terraforming.

I don't know if their method would work in an ideal world - but for purposes of illustration, let's suppose that it would. Then, what happens if some unplanned microbe takes over Mars, one which outcompetes your microbes and which doesn't have this behaviour? Either one that was already there, or one introduced by mistake, or one that evolved from the "daisy" species you introduced.

Most plans for terraforming Mars are more complex than this, involving many cycles, but run into the same issue. You have to be sure that all the cycles will work as expected, with the same types of organism as you expected. 

This World Is Black and White - Daisy world
Daisy world. The daisies have an optimal temperature for growth. The black daisies absorb more heat, so are a bit warmer than their surroundings, and do well when the climate is too cold. The white daisies do better when it is too warm.

As the sun heats up (as ours did) then more white daisies grow, and as they reflect away more of the heat, this cools down the planet so counteracting the extra heating effect. If the sun cools down, then the black daisies flourish, and as black absorbs heat, this cools down the planet.

This is a simple model of terraforming also. Cover the planet with daisies, black and white, and it should automatically regulate itself to the desired temperature. But what happens if some weeds grow on your planet that prefer much colder or much warmer temperatures than your daisies, or perhaps transform the atmosphere so it is poisonous to them?

For details see A PARABLE ABOUT A PLANETARY SYSTEM: Watson and Lovelock's Daisy World

As John Rummel (who was planetary protection officer for NASA) said in the same debate

"We need to know, before we go, whether or not, if we adopt a trajectory, are there martian organisms there? As we push Mars towards being more Earth-like, are there organisms there that will push back, that will do what we would consider to be socially unproductive things, like covering the planet with poisons? So let's think about whether or not Mars should be pushed in that direction. Once you make the decision, then I don't have a job anymore.".

Kim Stanley Robinson himself (author of the Mars trilogy) said in the same discussion

"The first question we need to answer is, is there life there right now alive, or not? When we answer that, and if the answer's in the negative, we can then proceed with essentially a dead rock that's very big and really interesting, and bringing life seems the obvious thing to do. A project which the industrial capacities of humanity may grow in ways that are as surprising to us as (our technology would be surprising to) the people in the 17th century."

"If we do find life on Mars, it will be very interesting to try to discover whether it is indigenous, which is to say a second start, and truly alien to us, a second genesis. In that case, I think we'll have to go and try to kill all the bacteria that are already there, inside the boxes that we've left, and try to clean up and really study it from a distance. That will be a really remarkable discovery, perhaps the major discovery in human history."


Everyone is agreed, I think, that we don't yet have the knowledge to be able to predict exactly what will happen if we try to terraform Mars. They are also agreed, I think that it is not guaranteed to work out.

It does no harm at all to think about the ideas. I think we can learn much from this. from that same debate again, this time, David Grinspoon

"We should be thinking about terraforming Mars. I don't think we should terraform Mars now, but as we think about it, we work the problem of how do we purposefully take care of a planetary climate. So I think that this exercise of considering terraforming Mars is very good for us, and is maybe a first step towards attaining the kind of wisdom that we need to someday be smart enough - not just technically, but also ethically and in terms of collective decision-making - to terraform Mars."

Where I think it can go wrong is if we then use these ideas to guide our space programs and future exploration of Mars. When we start planning as if future terraforming of Mars is a done deal, something that is bound to happen, that's when we fall into the trap of magical thinking, I think.

If we try to colonize and terraform Mars right now, I believe that the experiment is likely to fail. This might happen quickly, when colonists fail to establish a presence and die of accidents and other hazards on Mars, and we are unable to get emergency supplies to them in time from Earth. If that doesn't happen, it may fail more slowly, as our long term terraforming attempts run into one unanticipated issue after another.

Here is a photograph of a re-enactment of the Viking invasion of N. America.
Reenactment of the Viking landing at L'Anse aux Meadows, Newfoundland, Canada, 2000. The foremost longship is flying, from top to bottom, the flag of Iceland, the flag of Canada, and the flag of Newfoundland and Labrador., credit Joyce Hill
Things seemed so promising for the first year or two of their new settlement in N. America, but soon things began to go wrong. The same is likely to happen for prospective colonists to Mars, see Mars, Planet Of Surprises, Great To Explore Not So Great To Colonize - 1. Is It As Good A Place To Live As A Desert

We might learn a lot from a failure to colonize Mars, but we would lose the present pristine Mars. It's a one off experiment which we can never try again because we can never roll back the clock to the present day Mars.

Future generations might decide to terraform Mars. But they might also make many other decisions. And one thing we can be pretty sure about, that the future in our imagination, however vivid our imaginings, is probably far from the actual future in reality.

Our ideas about the future are likely to be as naive to future generations as the imaginings of the "hard science fiction" authors of the past who wrote about astronauts piloting faster than light spaceships with slide-rules, or a giant supercomputer made of vacuum tubes and spanning an area the size of Washington DC.

Earth and NASA
We have only one Earth. We also have only one Mars.

Let's care for all the planets in our solar system, and explore carefully, reversibly and responsibly. There is no hurry to terraform Mars, as the process would take millennia most likely and certainly many centuries. Let's find out what is there first.


This is an opinion piece which means, that I feel free to express strong views on the subject, for discussion, and I have not held back from presenting my own views. Do feel the same freedom to express your own views in the comments, and make this a lively discussion.


Trouble With Terraforming Mars

Ten Reasons NOT To Live On Mars - Great Place To Explore

"Ten Reasons Not To Live On Mars, Great Place To Explore" - On The Space Show

Telerobotic Avatars On Mars With Super-Powers ("Teleporting" from orbit) - Search For Life - And Long Term Exploitation

Would Microbes From This Astronaut Make It Impossible For Anyone To Terraform Mars - Ever?

Can Human Explorers Keep Mars Clean, For Science?

Is there Life in Venus Cloud Tops - Could XNA lead to Goodbye DNA - And do we need to Protect Earth (or Venus)?


Do you want to download this as an ebook, to read on your kindle, or kindle app (available for most operating systems)?

You can get it here:

Terraforming Mars - far into Realms of Magical Thinking (Amazon)

It's the same article with  addition of table of contents, so you can jump easily to any section, title page and formatted as a book. Text, images etc are the same.