I'm at the verge where I'm not certain I can take you seriously any more. Either you throwing things out in jest or you simply don't know. If the former, we're done, if the latter, I can educate you if you're willing to listen.
Do we know historical climates? Yes. Climates leave their marks all over the place. Ice cores, geological strata, fossils, etc... There are many ways to detect and correlate various data to determine historical trends in climate.
Do we know how far back humans go? Yes. Various species of humans in fact. As for our ancestry with apes, we shared a common ancestor. We did not evolve directly from apes (monkeys are different from apes....you can tell which is which because monkeys have tails). Could modern humans have lived in those conditions? No. Neither would our food (meat, fish and crops). That's why things evolved....adapted to fit in with the changes. The problem now is that the climate is now changing at the pace it used to. It's not slow enough for adaptations to keep up. We're also a much more populated planet today than even just 200 years ago (1 billion vs 7.5 billion today).
Do we intent to colonize Mars? Yes. Will Mars be a suitable habitat for 12 billion people in the next 100 years (current population projection)? No, not even remotely close. Nor will we have to means to transport that many people.
Same here since I'm wondering when we're going to get back to the original topic of paying for the wall but it seems you want to stay away from that.
I didn't question the climate historical data.
We only know based on what we've found, and to assume we've found everything is one bold assumption. How do you know for sure that we couldn't have lived in those conditions? There's been plenty of change already and we're still here. If it's tech that's aloud us to survive, then why can't it continue to based on it's ever rapid innovation and evolution?
How do you definitely know there will be 12 billion people in 100 years? Why will it be around 100 years before we can live on Mars if at all? I thought we only had 12 years? The expert scientists told us all so already.
The Canadian National Anthem According To Justin Trudeau