Reworked this + other ideas into Trouble With Terraforming Mars and To Terraform Mars with Present Technology - Far into Realms of Magical Thinking - Opinion Piece



Mars enthusiasts often speak about terraforming Mars as if it was an easy thing to do. They also often talk about sending humans to Mars first and then terraforming later. But if you think it through, you realise it is nowhere near as simple as that. It would be easy for us to make mistakes that will spoil Mars for humanity for billions of years.

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Simplest approach - mimic formation of Earth’s atmosphere, speeded up.

On Earth, our atmosphere developed slowly over billions of years. For a long time there was no oxygen, and no organisms that could consume oxygen. Over a period of time, the oxygen built up in the Great Oxygenation Event First the sea was oxygenated, then the land absorbed oxygen, and then finally it built up in the air. The last stage took a period of over a billion years.

On Mars the best way to terraform might be to do the same thing., but faster. You could try seeding it with photosynthesizing plants.

To give the oxygen producers a head start, you may want the whole surface to be covered in photo synthesizing plants first, before you start to introduce aerobes that will consume the oxygen. So start with lichens and algae that can create oxygen without anything else, as they don’t need soil in the conventional sense, just rock and water will do fine.

Plants will take 2,000 years or more to raise the oxygen in the atmosphere to levels where it is breathable (based on the time it takes on the Earth). For rapid terraforming, you will need to supplement them with artificial ways to create oxygen.

You have to warm up the planet too, to get it off to a rapid start. That could be done for with greenhouse gases, giant mirrors, or impacts from comets.

This approach needs care

Life can make significant changes to the atmosphere over short time periods. On Earth, then plant life sequesters 175 gigatonnes of carbon from the atmosphere every year. There were 766 gigatonnes of carbon in the Earth’s atmosphere in 1999; so on Earth, the entire atmospheric CO2 is cycled through plants approximately every 4.4 years.

So, other unintended forms of life in the mix can easily mess things up. They can consume algae or lichen, or compete with them for resources, and transform the atmosphere in unintended ways. To mention a few possibilities, what if they sequester nearly all the CO2, so thinning the atmosphere as fast as we try to thicken it? Or what if methanogens outcompete all the other lifeforms to create a methane dominant atmosphere? Or what if the aerobes remove the oxygen from the atmosphere as fast as you try to introduce it?

If you do introduce aerobes at an earlier stage, mimicking again the way our atmosphere evolved on Earth, this is likely to slow the process down. If you decide to do this all the same, you might need to do that carefully and select the ones you want to introduce with care.

Human colonists introduce over a thousand species in 19 genera just on our skin. We also have the micro-organisms in our guts, and indeed throughout our bodies in symbiotic relationships, and in food, and water. Many of these organisms in the human microbiome are actually beneficial for our health, e.g. break down sugars on our tongues. There is no way to sterilize humans of all these organisms without killing them.

This clearly can’t be combined with a stage by stage process of introduction of selected micro-organisms. Too early visits by humans would make a careful approach like this impossible.

Terraforming Mars will take centuries or millennia

In science fiction the process is often collapsed into a few generations of humans for the sake of a good story. However in practise, unless ways are found to speed it up tremendously, it is hard to see terraforming of Mars taking place in less than centuries.

So there is no urgency to get started right away :).

Science fiction and movies are not a reliable guide to the future

When you read early “hard science” science fiction, for instance early stories by Asimov, one thing you may notice is that astronauts use slide rules, punched tape and microfilm. After all, science fiction writers are children of their time. How could they be expected to foresee the invention of the micro-processor?

Then if you look at sci fi written before the Moon landings, it is striking that none of them predicted that we would watch the Moon landings live from Earth. Instead, their stories had the astronauts return to Earth to report their discoveries - rather like the captains of ships in the past. Perhaps they thought that because of the way the ionosphere reflects radio signals back to Earth.

There were striking predictions as well. For instance, early science fiction accounts of “television” long before it was invented for real.

It is pretty certain that modern sci fi stories are a similar mix of strikingly accurate predictions, together with errors that in the future would seem as anachronistic as slide rules and space voyages without communication with Earth. They never claim to be prophets :)

Other terraforming ideas

There are many ideas for speeding up the process, including crashing large methane containing comets onto the surface, use of large mirrors in space, and use of factories on the surface generating greenhouse gases, or directly transforming the atmosphere.

But attempts to speed it up could also go horribly wrong, e.g. the organisms on Mars remove oxygen from the atmosphere, and remove CO2 too, continually fighting against all your attempts to create a nice atmosphere for humans. Or they produce high levels of methane or sulfur dioxide.

We are nowhere near the stage of knowledge where we can say that any of these mehtods will work. Also we have no way to tell which is the best of all the options available.

Mars is not an exact twin of Earth

It would be tough enough if Mars was an exact twin. But it is further from the sun, has less gravity, and has hardly any magnetic field so exposed to higher levels of cosmic rays.

Also the atmosphere is so thin, you probably need to collide a few asteroids or comets with the planet to get it started. Indeed, it needs a thicker atmosphere than the Earth to achieve the same pressure at ground level, because the gravity is less.

Then there is less influx from the sun because of its distance. The thicker atmosphere will reduce the influx further, so the surface will get far less sunlight than it does on Earth.

Its orbit is much more eccentric than the Earth’s. This will make the changes of weather from winter to summer far more extreme.

Also, its axial tilt is greater, leading to large differences between the two hemispheres on Mars. Longer term the Martian axis is also thought to vary in tilt a lot more than the Earth axis because it doesn’t have the stabilizing influence of the Moon, and at extremes of tilt the summers and winters will vary in an even more extreme way.

It is generally recognized nowadays that our atmosphere on Earth is kept in balance through the interaction of many different cycles (the weak Gaia hypothesis that most scientists support). To get Mars to work, it needs its own weak Gaia to be established. We can’t expect this to happen instantly and automatically.

If you could magically transplant the plants, animals, seas, atmosphere and everything from Earth to Mars overnight or duplicate it exactly - it wouldn’t work, not for long. It would go into some other equilibrium and would surely have a period of wild swings in the climate before it settled down, I don’t think anyone can know how it would end up eventually.

Mars needs a new equilibrium of its own different from Earth

On Mars we have to start up a new atmosphere, forests, seas, and ecosystem on a new planet. Also, it has to be a different solution from the one on Earth.

Yet it must still work and last for long periods of time, without wild swings of climate, and without everything going out of balance. We simply don’t have anywhere near the level of knowledge to do that successfully right now.

We can certainly transform Mars. But if we do it unskillfully, it may become inhospitable for human colonists in the long term.

Ways to gain experience in terraforming on a small scale first

We will encounter a similar problem but on a smaller scale when we make self sufficient habitats starting from just bare rock and water. This has great advantages for novices in terraforming such as ourselves. If things go really badly, you can evacuate the atmosphere, sterilize the soil, and start again. You can also modify the atmosphere relatively quickly to correct smaller mistakes, and scrub out noxious gases.

As colonies get larger, especially if we create large kilometers wide habitats like the Stanford Torus, then we will get even more experience. We will also have better knowledge of Mars, and the Martian soil. We will be able to do large scale experiments to see what is likely to happen if you introduce different micro-organisms to it, or vary the composition of the Martia natmosphere.

We are also likely by then to have spectroscopic observations of the chemical composition of atmospheres of Earth and Mars sized exoplanets around other stars. We can study what happens to them. Some of them may even turn out to have life, detectable by imbalances in the atmosphere. If so we may then have a variety of reasonably accurate models for habitable planets of different sizes, composition and levels of “sunlight”, to draw on for terraforming.

We can also “terraform the Earth” - by that I mean reversing desertification, and restoring tropical rainforests. When conditions on Earth are stable, and we have large scale habitats in ecological equilibrium, and hopefully some examples of exoplanets with life for spectroscopic study, we can begin to think about terraforming other planets with a bit more confidence.

Future of Mars after terraforming, over geological timescales

Some people don’t worry about this and argue, we only need to care about the next few generations. But for me, the living beings who will inhabit Mars or Earth hundreds of thousands of years into the future, or millions, even billions of years from now, are also still beings like ourselves, and I feel we do have responsibility towards them.

So, a very important consideration for long term terraforming, is that Mars has no continental drift. Our atmosphere is maintained by the CO2 from the volcanoes - CO2 dissolves into our seas, turns into limestone, and then eventually comes up again as CO2 in volcanoes. On Mars, without the volcanoes, the CO2 will be lost from the atmosphere permanently.This means that Mars will lose its atmosphere eventually on geological timescales. Once this happens, it will be hard to reverse, with the CO2 now in the form of limestone rather than dry ice.

This could happen as soon as hundreds of thousands of years in the future; a blink in the geological timescale. It will also lose its atmosphere faster than on Earth by other processes due to the weaker gravity, but that’s a longer term process. The consensus seems to be that the loss of CO2 as limestone is the more immediate issue over shorter geological timescales.

On longer timescales then Mars will also lose its atmosphere more rapidly than the Earth because of its low gravity. It is easier for the lighter gases to leave the atmosphere.

I see a couple of issues with this. First, there may be a vital need to terraform Mars in the future. By terraforming it now we may make it impossible to re-terraform it in the future when it is really needed. It might for instance be needed when the sun goes red giant and the Earth is no longer habitable. Eventually the sun will expand so much that the moons of Jupiter will become habitable but.before, then for a while, Mars may be the “des res” of the solar system for planetary surface inhabitants.

Another consideration is that the beings who live on Mars when it loses its atmosphere (possibly our remote descendents) may no longer have the technology at that stage to leave the planet, or to do anything about the atmosphere.

If we terraform it wisely now, perhaps some way can be found to do this so that it will still be inhabitable billions of years from now. But we don’t yet have the understanding and technology to do that.

Ethics of terraforming

Terraforming Mars is something that affects all humanity. So it is important that it is debated, and not just done by fiat, by a small group of enthusiasts keen on one approach.

In this great debate, you have those who are for it, and think it should be done right away as soon as possible; and those against it; and then the interesting middle ground advocated by researchers such as Christopher McKay.

In the middle ground, the idea is, that if Mars does have life already established, then we should Marsform it (to coin a word), rather than Terraform it. I.e. manage Mars so as to foster the life it already has, and let it follow its own different pathway from Earth.

This could be really interesting, and the life on Mars might be able to do things that life on Earth can’t do. Especially if it has a different biochemical basis or in some way is very different from Earth life. See Ethics of Terraforming - Criticism (Wikipedia) - I found this quote from Christopher McKay in Wikiedia

“If we discover living or dormant organisms on Mars and these forms represent a different type of life than the life we have on Earth, then we should not bring life from Earth to Mars. Instead, we should alter the Martian environment so that this native Martian life can expand to fill a planetary scale biosphere. …” …it is essential to maintain the categorical distinction between killing individual microorganisms and extinguishing an entire alternative system of life. There is no logical argument against killing microorganisms per se, either for research, medical, sanitary, or even casual reasons. However… it does not logically follow that destroying or displacing the first example of life beyond Earth is acceptable if the only examples of that life are microscopic. … “If we terraformed Mars to allow the expansion of that life we would then reap the maximum benefits from the scientific study of that life form and its development into a full scale global biosphere. We would also enjoy the educational and [aesthetic] benefits of life in a biologically richer solar system.” (from “Do Indigenous Martian Bacteria have Precedence over Human Exploration?”, pp. 177-182, in ON TO MARS Colonizing A New World, by Christopher McKay and Robert Zubrin)

Mars is not needed for colonization urgently

Space enthusiasts often argue that we MUST colonize Mars because it is important for humans to create permanent settlements outside the planet Earth.

However, there is much more living area available for human expansion into space than there is on planetary surfaces. In the long term there is room for trillions of people in space habs, and only room for billions of people on rocky surfaces.

There is enough material in Ceres alone to construct habitats for several hundred times the surface area of the Earth, and to house trillions of people. Deimos alone has enough material to construct a habitat with the area of Nepal.

In the early stages too, the easiest locations, most likely to be a commercial success, are the Moon or colonies orbiting the Earth or Moon.

When you realise this, terraforming of planetary surfaces no longer seems urgent. That’s especally so since any mission that sends humans to the surface will pre-empt longer term decisions about what to do.

For as long as we are unsure about the outcome, it does no harm to just wait. There is absolutely no urgency about terraforming Mars.

Our main options

Keep Mars pristine

Marsform it

Terraform it

Just land humans on it and let it develop whatever way it happens to go

Anyone who advocates colonising the surface of Mars right away is making the last choice. Also they are making the choice, not just for themselves, but for the whole of humanity.

I would argue that we simply don’t have the level of understanding available for anyone to make that decision in an informed way. Even the advocates of colonization might find that they would make a different decision if they knew the full impact of colonization of Mars.

Many scientists would agree with this. Here is a quote from LIsa Pratt, a Nasa astrobiologist, when interviewed by the science correspondent for the Guardian (UK magazine)

‘It is very depressing. Before we have even discovered if there is life on Mars - which I am increasingly confident we will find - we are talking about undertaking massive projects that would wipe out all these indigenous lifeforms, all the strange microbes that we hope to find buried in the Martian soil. It is simply ethically wrong.’ … 'If we find life on Mars, the philosophical implications will be profound. If it is unlike Earthly life and has a different genetic code, this will show that living beings evolved separately on two neighbouring worlds. Life is therefore likely to be ubiquitous throughout the galaxy. 'If it has the same genetic code, however, it will indicate that one planet must have contaminated the other - probably by rocks being blasted across the solar system following meteorite impacts. We may really be Martian in origin. 'Given the importance of these issues, we simply cannot risk starting a global experiment that would wipe out the precious sensitive evidence we are seeking. This is just not on.’

Prestige and dishonour of “Set a foot on Mars first"

Many would be colonists especially for Mars One are motivated by the wish to be amongst the first to set foot on the surface. It is also possible that nations, organizations and groups of enthusiasts might compete for the prestige, like the "Race for the Moon”.

However, this prestige could quickly turn to dishonour if they find after the event that they are known through history as the nation or group of people who were responsible for contaminating Mars and making it impossible to terraform it - or the people who caused the extinction of native life forms on Mars, or who so messed up the fossil record of organics on Mars as to make the origins of life there hard to impossible to completely disentangle.

Can we keep Mars pristine and permit human exploration of the surface?

Some say that only humans can explore Mars. The reasoning is that with robots it will just take so long as not to be worth doing.

Perhaps that used to be true. Nowadays with telepresence the situation is changing dramatically, or rather, the distinction is getting blurred.

With telepresence, a surgeon on Earth can operate on a patient a thousand miles away, something which has actually been done. With the use of omnidirectional treadmills, you can walk and even run in any direction over a virtual landscape.

To operate machinery or robots by telepresence you need to be close by on astronomical scales. We can’t operate robots by telepresence on Mars from the Earth. But astronauts in orbit around Mars can easily operate robots on the surface.

They will be able to walk and run for miles over the Mars landscape on their omnidirectional treadmills, all the time never moving away from their room inside the space hab. The telepresence rooms can even be maintained at Mars gravity conditions.

You could have zero g in the centre of the spinning hab, Mars gravity and the telepresence units part of the way out - and sleeping and living quarters and greenhouses etc at full Earth gravity furthest out of all. The habitat doesn’t need to be very large to do this.

They will be able to rive around on the surface at normal speeds. The reason current Mars rovers are so slow when operated from Earth is mainly because of the light speed delay for controlling them. There is no incentive to make them faster because they would be impossible to control safely from Earth.

With telepresence, we can use the Mars Direct idea to create fuel on the surface. Then we an use that to power the next generation of rovers. We can even have small spacecraft on the surface capable of suborbital hops - not too hard with the atmosphere so thin.

We can do mining too, there are already plans to drill deep below the surface. With rigs operated by telepresence we can dig kilometers deep if needed. And indeed even set up factories on Mars and export anything of value on the surface to the rest of the solar system, all without any need for humans to set foot on the surface in person.

Background Material

There is plenty of reading matter available on these issues. Here are a few links to get you started.

For long term future of the solar system: Living in a Dying Solar System, Part 1, Living in a Dying Solar System, Part 2 (Ray Villard, Astro Biology Magazine, 2009)

For the physical feasibility of terraforming Mars (but ignoring the biological issues) see Terraforming Mars (Wikipedia)

For biological process of terraforming Mars see How to terraform mars: an analysis of ecopoiesis and terraforming research

For a detailed overview of terraforming issues on Mars see Biology and the Planetary Engineering of Mars (by the microbiologist Julian A. Hiscox)

For ethics of terraforming, article in the guardian: Now Nasa looks to change Mars into a garden of Earthly delights and the wikipedia article Ethics of Terraforming also Christopher P. McKay Planetary Ecosynthesis on Mars: Restoration Ecology and Environmental Ethics. Here is a youtube video with Christopher McKay talking about ethics of terraforming Mars. There are many recent papers on the ethics of terraforming.

For a survey of some of the orbital mission suggested for Mars with many links, see Manned mission to Mars - exploration of the surface from orbit via telerobotics and telepresence (wikipedia)

See also the wikipedia section Manned mission to Mars - Contamination concerns for surface missions to Mars



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