Why leave Earth?

Would you leave Earth if you had to? Why would we need to leave at all?
29 May 2018

Interview with 

Adrian Currie, Cambridge University


Earth from space


Last year, one very prominent Cambridge scientist, Stephen Hawking made a rather shocking prediction. He stated that to secure the future of us humans, we need to colonise another planet. But would you want to go? Izzie Clarke put it to the public and then asked Adrian Currie, from the Centre for the Study of Existential Risk about why we may need to find another home...

Stephen Hawking - I strongly believe we should start seeking alternative planets for possible habitation. We are running out of space on Earth and we need to break through the technological limitations preventing us living elsewhere in the universe.

Izzie - Professor Stephen Hawking stated that to secure the future of us humans we need to colonize another planet. But would you want to go?

Person #1 -  Definitely not!

Person #2 - Yeah, it’d be an adventure. Something new, exciting

Person #3 - And I get a holiday. Probably not to live there.

Person #4 - I don't know. You have to have some entertainment, otherwise it’d be a bit lonely wouldn’t it?

Izzie - But why would we need to leave planet Earth? Existential risk is the risk to the existence of something and in this case that something is us. As Adrian Currie from Cambridge University explained

Adrian - So one set of them, are things that are done to us. So take for instance a large asteroid hitting the earth or a super volcano erupting or a major solar flare. Basically a big gust of radiation coming out from the sun. There are also dangers that we do to ourselves. Climate change - one of the things we know that's going to happen with climate change as an increase in the global water levels. What's that going to do? Well it's going to mean a lot of people are moving. So the upshot of this is there's going to be a large number of climate refugees. What's an upshot of a large number of climate refugees? Well we can sort of tell from history that often this creates pressure on certain types of political systems and so the political environment becomes a lot more problematic. At the same time with large amounts of movements of people that increases the chances of epidemics. Right so you might have a lot more disease going on. In addition to that with climate change is going to be many more as it were smaller disasters  - more droughts more tsunamis. At the same time of course you've got various types of biodiversity collapse which is linked to climate change and we really don't know to what extent living systems are dependent upon certain levels of biodiversity being maintained. When you start thinking about all of these things happening at the same time you can sort of see it's a perfect storm. Would it lead to human extinction? I'm not sure, but it's at least reasonable to think that it's going to put a lot of pressure on our species and it's certainly going to put a lot of pressure on our civilizations.

Izzie - So pretty ideal to have like a backup plan if something like that is going to happen!

Adrian - Yeah. And I take it that's one of the sorts of motivations for wanting to colonize other planets. But I think we should care about a lot more than just human survival. We also care about our lives being good. And moreover we care about the whole population. The idea that we might let the vast majority of the human population die so we can then have a few survivors on some other planet seems in itself deeply problematic.

Izzie - How can you even model something like this? Because obviously there’s a quite low probability of these things happening, but they have a very high risk.

Adrian - It's incredibly difficult. Some of it involves just using what we do know about for instance planetary systems, we can model things like what happens when great big rocks hit the earth. We can model things like what happens when different economic systems sort of run into each other and that can start giving you some kind of hint into how these things work. But I think the real question in a sense is not how do we know about these things but rather how do we manage the fact that we don't know about these things?

Izzie - Say if we didn't have something like climate change going crazy or maybe even something like really strong solar flare. Is there a way that we could defend ourselves?
Adrian - Potentially! We have this new technological power with the case of solar flares. We know that if an extreme solar flare happened that would knock out all of our space technology. And so what you want is some kind of backup system, maybe I don't know a bunch of satellites on standby on earth but you can just shoot up, if this were to happen. So one of the advantages of these new technologies is that they enable us to defend ourselves against these old existential risks. Things like great big rocks. But they also present these new existential risks that come from emerging technologies.

Izzie - What do you think some of the threats might be if we did colonize another planet?

Adrian - One scenario that comes up off the bat and science fiction is the idea that if we were colonizing other planets they might be other life there and other life might have new types of parasitism. They might be particular diseases there that we're not equipped to handle. So you have a sort of space analogy between what happened when Europeans colonized the Americas and bought this new bunch of diseases that the indigenous people just hadn't had time to get immunities to. Maybe there are things like that but there are other ways of thinking about this as well. So one reason why we might worry about colonizing other planets is we're going to create isolated divergent groups of humans. And there are going to be highly technologically advanced but isolated. And there's a chance that there could lead to wars between these groups. And that seems very very bad.


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