Is it ethical to colonize Mars?

Story highlights

  • Brian Green: What is the moral value of native Martian life vs. creating a "backup Earth"?
  • It would be hubris for us to assume that humanity on Earth would last forever

Brian Patrick Green is assistant director of campus ethics at the Markkula Center for Applied Ethics and lecturer in the School of Engineering at Santa Clara University. The opinions expressed in this commentary are solely those of the author.

(CNN)With the recent NASA announcement of liquid water flowing on Mars and the movie "The Martian" making a splash at the box office, we might well ask whether humans should go to Mars.

There is almost no chance that Mars has intelligent life and for decades we earthlings have dreamed of living on Mars. But let's think about this from an ethical point of view. What is the moral value of native Martian life vs. creating a "backup Earth"?
The discovery of native life on Mars -- even if it is only the most primitive microbes -- would be one of the most important scientific discoveries in human history. Sound improbable? NASA does not think so; in fact, determining if life ever arose on Mars is its first goal for Mars exploration.
Brian Patrick Green
NASA has evidence from Earth that life can growth in very extreme conditions. These life forms are called extremophiles, and they can survive under high temperature and pressure, endure intense radiation and cold. Life may have evolved eons ago on Mars, and just been driven underground.
Should we respect native Martian life forms if we find them? Most likely they would be microscopic. On Earth, we kill microbes all the time. So is it wrong to go to another planet and mess with the natives? After all, if that had happened to Earth in the past, we might not exist.
How thoroughly do we need to search for life forms before we can declare Mars ours? Should we leave the planet as a preserve if there is native life, or settle down and assume that native life will remain relatively unharmed? Should we intentionally restore the Martian climate by warming the planet and adding water so that whatever life is there may better flourish?
In the absence of proof of life on Mars, this is a philosophical debate. But we may not have the luxury of an exceedingly thorough search for life before humans start to contaminate the planet with Earth life (humans carry a whole microbiome of organisms, after all). There are humans at this moment planning to go to Mars and permanently settle there.
Several organizations have already stated they are going to Mars as soon as possible, and SpaceX's Elon Musk has been clear on one reason why he thinks it is so important for humans to go to Mars.
Musk believes that living exclusively on Earth is too risky. Humanity is keeping all of its eggs on one planet, and given the natural and human-made risks in the universe that is simply not safe.
The moral value of having a "backup Earth" shouldn't be underestimated.
You might think -- what's the chance of humans destroying humanity? Look at how far we've progressed in the last thousands of years. Sure, we have empires rise and fall, but we won't destroy ourselves.
But with technological progress making nuclear, biological and chemical weapons easier to obtain (not to mention new risks like artificial intelligence and nanotechnology), and the unintended consequences of climate change, doomsday scenarios are real possibilities in the future. It would be hubris for us to assume that humanity on Earth would last forever.
Now, consider this scenario: a nuclear war or other disaster hits the Earth and human civilization is destroyed. Everything in history -- all art, progress, science, technology -- is for nothing.
Then consider if the same thing happens, but a small city full of humans -- perhaps a few thousand in a self-sustaining settlement on Mars -- exists with records of human history, with animals and plants, children and couples.
In the second scenario, despite the horrific disaster on Earth, all of human history is not for nothing. There is still human meaning in the universe. That's an incredibly morally valuable thing.
It's clear that the backup Earth project should take priority, even if it is potentially damaging to native life on Mars. We could try to settle on the moon or a large asteroid instead, but as things look, Mars is our best option.