@jasjas1973, I don't think western overconsumption was ever truly sustainable and we will have to adapt rapidly. However, the human race happens to be quite good at that. The aim now is to stop it from getting any worse (the "wet bulb" concept genuinely terrifies me).
The earth is a lot more resilient than we give her credit for. It has been worst-case scenario hot before (50 million years ago) and the temperatures gradually lowered...the only problem is that it takes millennia for it to happen, so we are not talking about a human timescale. Forests grow, die and become coal locking the carbon away into the soil. We just decided to release it all in the course of two centuries, like a crazy teenager burning down the house "because we can".
I agree, the 1990's probably were the tipping point. I don't agree it's hopeless.
@Lockheart the birthrate is dropping in every country. I think it's 1.7 globally, at the moment (depends on who you ask). Experts are more worried about a baby bust than a baby boom. The reason why our population is continuing to grow is due to a longer life expectancy. Unfortunately, that will also be one of the first things to suffer with climate change - older people are at increased risk from heat.