Indeed. For example concerning glasshouse gases, we need to come back to 1990's emission levels because that's what the Earth can absorb. The problem is, we're

Indeed. For example concerning glasshouse gases, we need to come back to 1990's emission levels because that's what the Earth can absorb. The problem is, we're about 1bn more, our levels of consumption are still soaring, and citizen of new nations deserve to emit as much carbon as we do. Once we transfer the carbon limitations to every individual in developed country, we'll all throw our arms in the air saying "That's oppressive!". Example: When the Greek people learnt they had to pay the same taxes as the rest of Europe, they all started blaming Germany for being over-controlling and penny-pinching, and looked in the way of Putin. Imagine what would happen when our citizens understand that 90% of the people can't have meat, heating, cars or flights. Hence, carbon limitations will create tensions, country-level protests, and probably wars, which will waste even more carbon than today. Added to the global warming which is already underway, and there's little hope to dodge a catastrophic event. Either we manage carbon properly and most of us survive with greatly reduced materialist life (e.g. no meat), either we have a big event and 5% of lucky humans survive anyway, with a greatly reduced materialist life. Concerning Mars, launching the Human civilization on other planets doesn't sound like a desirable goal to me. We didn't even succeed to manage ours, why expanding? Notably, none the people you've ever met will be saved by Mars – Only samples of our race will be sent. We'd better send a Noah's Arch than Humans.