Mars: barren, inhospitable and dead. This is how most of us recognize the red planet, yet eons ago our neighboring planet wasn’t just another speck of rock in the infinite of space. We now know for certain that Mars once harbored a thick atmosphere, flowing rivers and quite possibly life. It used to rain so hard on Mars (with water) that it shaped the planet’s geology. In most respects, many millions of years ago, Mars used to be very similar to Earth. If it was once in a state where it could foster life, then, theoretically at least, this state can be reversed. Enter the fascinating world of Terraforming.
Terraformingis the process of transforming a hostile, extraterrestrial environment into one suitable for human life. While the idea has been introduced in many SciFi books or movies, some scientists take terraforming extremely seriously. The world famous astrophysicist and science communicator, Carl Sagan, once said that he sees an immense potential for science in the search for life on Mars. If life was indeed once present on Mars (it might still be today, though highly unlikely near the surface), then scientists might be able to gather key insights and clues that could explain how the planet become so cold and lifeless as we know it today. Armed with this knowledge, there are (herculean) practical solutions that can be applied in a reverse step process to revert the planet back to life.
Sadly, Sagan never lived to see the rover missions land on Mars: Spirit, Opportunity and the famed Curiosity. The latter is the biggest and most advanced rover to land on Mars, tasked with the primary mission of identifying signs of ancient Martian life. So far, it’s doing a pretty job having discovered new signs of water and even organic molecules.
How terraforming works
If we do get it right, how would a Mars Terraforming scenario look like? Well, according to Christopher McKay of NASA’s Ames Research Center at this point the likeliest course of action would be to release immense amounts of chlorofluorocarbons into the Martian atmosphere. CFCs or Freon, as they’re also called, have been widely used as refrigerants, propellants (in aerosol applications), and solvents until they were found to cause massive damage to the ozone layer in the upper atmosphere, and consequently were banned. (surprise, surprise! someone’s still using them).
At the same time, CFCs are the most potent greenhouse gases, molecule for molecule. One type of CFC, CFC-12 or “Freon-12” as it is known by its trade name, is 17,700 times more potent than carbon dioxide at trapping heat. A huge payload of CFCs — derived from soil and air and manufactured in factories which would suck up the power equivalent of a large nuclear power plant — would be delivered to Mars and released into the atmosphere. At this point, the CFCs will trap more heat from the sun to the point where surface temperatures would rise by some 4 degrees Celsius. This should be enough to spark a climatic chain reaction as various subsystems feed each other in the loop.
Releasing the greenhouse gases serves a double purpose: boosting atmospheric pressure and boosting the global retention of infrared radiation. Essentially, this is what the ‘greenhouse effect’ does.
The idea is to bring atmospheric conditions closer to Earth’s. The Martian atmosphere is 97% carbon dioxide which might sound like a global warming nightmare (though that’s a distinction reserved to Venus) but for full context, we have to keep in mind that in terms of pressure, its atmosphere is a lung-emptying 1/1000th of Earth’s atmosphere.
“If you want Mars to be more Earth-like you’re going to need to make the atmosphere thicker,” says Michael Chaffin, a researcher working on NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. “Looking at the history of Mars, we know that early on the atmosphere had to be thicker to support water.”
The Martian atmosphere is also much less opaque to infrared radiation (IR) than Earth’s. Mars has an IR ‘optical depth’ (how efficiently light gets stopped) of about 0.2 while Earth has 0.83 and Venus has 60. Since it’s so thin and cold outside, liquid water — essential for any human colony — can only withstand the surface for brief periods of time.
“If you took a glass of liquid water to Mars and poured it out, some of it would freeze, and some of it would boil away, but none of it would remain liquid for very long,” Chaffin says.
A huge payload of CFCs — derived from soil and air and manufactured in factories which would suck up the power equivalent of a large nuclear power plant — would be delivered to Mars and released into the atmosphere. You’d need about 3 times the total amount of CFCs ever manufactured by humans to date. At this point, the CFCs will trap more heat from the sun to the point where surface temperatures would rise by some 4 degrees Celsius. This should be enough to spark a climatic chain reaction as various subsystems feed each other in the loop to terraform Mars.
The increasing surface temperatures would vaporize some of the carbon dioxide trapped in the south polar cap, which would end up in the atmosphere and further cause more heating. The temperature would be enough to melt the ice and provide liquid water needed to sustain life. The added liquid water would raise the atmospheric pressure to the equivalent of that found in the highest mountaintops on Earth. Far from being survivable, it would be enough to start growing plants and trees that thrive on CO2 and produce oxygen. In March 2017, scientists grew potatoes in Mars-like soil and conditions akin to Matt Damon in The Martian, so that’s doable already.
Mars terraforming methods
The CFC Mars warming method was proposed in 1984 by James Lovelock and Michael Allaby’s book,The Greening of Mars.
Other methods that might work to raise atmospheric pressure and greenhouse gases in the atmosphere involve:
Detonating thermonuclear bombs at or above Mars’ ice cap poles. The reasoning is that there’s a lot of CO2, methane and other greenhouse gases trapped in the ice, just like here on Earth. Melting that ice via a thermonuclear blast will release the CO2 and warm up the planet, something Elon Musk mentioned briefly during an appearance on The Late Show with Stephen Colbert.
Using giant mirrors in space to focus massive solar energy onto the polar regions just like you’d use a magnifying glass to burn a scrap. The mirrors would have to be humongous — at least 125 kilometers in radius to raise polar temperatures by around 5 degrees Kelvin.
Dump ammonia into the atmosphere of Mars. It’s a potent greenhouse gas, although not as potent as CFCs. However, it has the added benefit of adding nitrogen gas to the martian atmosphere.
Spray paint the surface of the planet so it’s less reflective — essentially, albedo reduction. This could be anything from dark dust collected from Phobos and Deimos (two of the darkest bodies in the Solar System) to extremophile lichens and plants that are dark in color. Carl Sagan himself published a famous paper on the subject in 1973.
Another extreme measure might involve importing methane and other hydrocarbons from the outer Solar System where it’s plentiful.
One of the most exciting Mars terraformation pathways was recently proposed by NASA’s Planetary Science Division director Jim Green who suggests encapsulating the red planet in an artificial magnetosphere. For this to work, we need a huge electric circuit or dipole that can generate enough energy to cover the entire planet in an artificial magnetic field. We’re looking at two oppositely charged magnets connected to inflatable structures and placed in orbit somewhere between Mars and the sun. If this sounds preposterous, so do the other methods. Terraforming Mars is not an easy job or for the faint of heart.
Is terraforming Mars a good idea?
Even so, producing an oxygen-rich atmosphere is just the tip of the iceberg. Scientists would still have to find a way to address the myriad of other problems like:
no magnetic field to shield from radiation and sputtering of the atmosphere;
no plate tectonics to recycle carbon and water and rebuild eroded land;
no large moon to stabilize the axial tilt and provide tides;
much more elliptical orbit, which means much more erratic climate;
much higher rate of impacts due to the proximity of Jupiter and the asteroid belt;
gravity only .38 that of Earth;
No mountain chains to break up atmospheric currents and release precipitation;
surface covered in toxic perchlorates and asymmetry between hemispheres means all land on one side and all ocean on the other.
even with this out of the day, there’s still the issue of:
it would take centuries to build enough oxygen to breathable levels;
we might fail miserably since climate is super complex;
because it’s not geophysically active, Mars might actually take thousands of years to become habitable;
some things will never be the same on Mars as on Earth. Take gravity, for instance, which is almost a third that on Earth. Studies carried out in weightless environments such as on the International Space Station cause bone demineralization, but also muscle atrophy, immune system effects, and other complications throughout the body. It’s foreseeable similar effects occur in partial gravity. In time, humans living and breeding on Mars would evolve radically different. They’d become much, much taller than Earthlings because of the reduced gravity.
The whole process is long and tedious requiring at least a couple hundred years. It’s not like flicking a switch – immense amounts of resources, energy, and most likely human lives would have to be sacrificed. So, why would humans want to terraform a planet that’s millions of miles away in the first place? Personally, I believe Mars is the next obvious step for man. If humans are to ever become more than just a mono-planetary species, hopefully, an interstellar one, then we need to move our Earthling butts out of here.
Of course, there’s another important concern that needs to be addressed. As we stand today, humans aren’t doing too good a job of taking care of their own planet. A Mars terraforming mission couldn’t start earlier than a couple of decade into the future, maybe even a century. By then, we’ll either blow any chance of living in peace and prosperity on this planet or we’ll become advanced enough, both technologically and socially, to make a planetary leap and finally shoot for the stars. Even if things go horribly wrong on this planet because of runaway global warming, attempts to produce global warming on Mars will teach scientists to do the reverse back here on Earth, possibly making up for damage in pollution and deforestation.
Tibi is a science journalist and co-founder of ZME Science. He writes mainly about emerging tech, physics, climate, and space. In his spare time, Tibi likes to make weird music on his computer and groom felines.