[palata]

> so if we assume that Mars has the raw materials we need, and is just lacking an atmosphere, then it seems likely (just spit-balling here) that a million people could get the job done

Hmm... I don't get how it seems likely that a million people could get the job done. I mean really, we are destroying the conditions necessary for our survival on Earth. It's not like we know how to survive in a place (Earth) that just requires us to change nothing. Why would we be able to survive in a place (Mars) that requires us to create from scratch the very conditions we can't seem to maintain on Earth?

[gcanyon]

I'm not sure I understand your point. I'm not an expert, but "conditions necessary for our survival" == about 7 things in (rough) order of immediacy:

   1. Breathable air
   2. Survivable temperature
   3. Shelter from solar radiation
   4. Drinkable water
   5. Food
   6. Energy to support the previous 5
   7. Raw materials to support the previous 6

I postulated the 7th item, so let's take the previous 6 in order:

   1. We know how to generate breathable air and keep it under pressure. We do this in nuclear submarines.
   2. We know how to insulate habitats. We cope with a roughly equivalent temperature at Antarctica.
   3. We know how to protect against solar radiation. We (somewhat) do this at the ISS, and we have plans to do it on lunar base.
   4. We know how to produce water as long as we have raw materials to work with.
   5. We can grow food in pretty much any environment we ourselves can survive in.
   6. We can generate power in almost any environment if we have raw materials.

We are not "destroying the conditions necessary for our survival on Earth." -- we are significantly changing the environment on Earth, that is true, but not such that we will all die. Has any credible person presented evidence for that outcome?

[palata]

> I'm not sure I understand your point.

I guess my point is that though we know how to make a few humans survive in space (with constant support from the Earth) and we may know how to make a few humans survive on Mars without constant support from the Earth, I am not at all convinced that we know how to make millions of people survive on Mars.

Take point 6 for instance: power. One of the biggest problems we currently have on Earth is that we don't know how to replace fossil fuels, and fossil fuels are not unlimited. It's currently unsolved, and it will impact our lives heavily in the next few decades.

> We are not "destroying the conditions necessary for our survival on Earth."

We are, most definitely. Where the air humidity is saturated (so take a strip around the Equator), if the air temperature goes higher than the skin temperature, we can't regulate our own temperature anymore (by sweating). So we can't live outside without life support.

If we reach an average increase of 4 degrees, then 1/3 of the world population will be located in places where humans cannot survive outside without life support. And right now we are most definitely going for those 4 degrees.

Now you may not care because you don't live around the Equator, but... imagine a world where 1/3 of the population must relocate in order to... regulate their body temperature properly. And I am not even talking about the impact on agriculture in the rest of the world where you can still regulate your body temperature (because at some point you need to eat). In such a world, if you are lucky enough to be in a livable location in terms of temperature, you may just not have food. Definitely global instability and wars.

Not everyone will die, but you have to realize that everybody will be affected greatly.

[gcanyon]

Fossil fuels are becoming less and less necessary to human life, and we have solar and nuclear in pretty reasonable shape to make synthetics as long as we have the raw materials.

Sorry, I took "destroying the conditions necessary for our survival on Earth" to mean in general, as in universally. We're certainly not doing that.

Just as a rough guess something like 15 percent of the land surface of the Earth is near-completely inhospitable to humans, and we're increasing that by 1-3% per century? (both guesses) I don't find it difficult to imagine 1/3 of the earth's population relocating over the course of a few centuries.

I'm an optimist, but I think "everybody will be affected greatly" is pessimistic. Technology and affluence make up for a great deal of negative environment (check out the growth around Phoenix) and the world is becoming more affluent.

[palata]

> Fossil fuels are becoming less and less necessary to human life

This is completely wrong. We can't even build renewable infrastructure without fossil fuels right now, by very far. Without fossil fuels, today, big cities simply die because food doesn't get there anymore. Are you seeing electric trucks coming along? I mean not in a pitch for VCs, but in a realistic way, at scale?

> as long as we have the raw materials.

Ever checked the status of raw materials on Earth? :-)

> I don't find it difficult to imagine 1/3 of the earth's population relocating over the course of a few centuries.

You vastly underestimate climate change. Problems are starting right now, and the time scale is rather decades than centuries. Not to mention that it's not "planned relocation" where we organize it over a few centuries: when people start moving, they will move massively. At that point it will result in global instability and wars. Imagine whole countries emigrating... with their military.

> but I think "everybody will be affected greatly" is pessimistic.

From my point of view, not even realizing that we have a problem now is making things worse (because we need to act really badly).

[bluGill]

Note that mars is the most likely candidate to make self supporting. I too am not sure if we can, but everywhere else in our solar system is harder.

[palata]

That's my point: it's clearly extremely difficult (much harder than surviving on Earth), and it's still infinitely easier than going in another solar system.

The vast majority of people won't go to Mars, but will pay the consequences of climate change, biodiversity loss and fossil energy. Still not only nobody cares, but many keep dreaming about Mars.