The next ice age will be a much bigger problem, since it will literally erase mankind from the planet. It is due in the next 10 thousand years or so. Now if you consider that agriculture only started about 5 thousand years ago and the pyramids were built about 4 thousand years ago, while the Roman Republic started about 3000 years ago, you will better understand the severity of it. We donâ(TM)t have much time left to settle Mars, but global warming is the least of our worries.