Couple of points:
- As I have said (and proven by science), previous ice ages came and ended very-very quickly (in a matter of years or decades with 5-15 C swings!), probably even quicker than the current era of AGW, so the idea that ecosystems will not be able to cope is quite groundless...to which you reply: but those were "intact" ecosystems. Well, it does not matter. Adaptation speed is not dependent on species number, it is based on adaptation speed.
- but, but: precipitation patterns will change. YES, they will. We had a Green Sahara just 5 k years ago, and forests in Central Asia. This is nothing new. We might even see the Sahara greening again!
- permafrost: I attach a map of the permafrost. Cca 1 million million people live in those areas in NA (750k in Alaska and at most 250 k in canada), and a maximum of 3-5 million in Russia (the whole of Yakutia eg has only 1 million people on 3 m sq km!!!) and it is not a surprise, it's not nice there. This is a non-issue relative to the size of the economy
- NZ: I think more people will die of earthquakes there during this century than due to climate change. It is very much protected, probably one of the biggest winners
- human population: this is absolutely true, there are simply too many humans for this planet, but I do not think that any of you would have an IMMEDIATE solution
- if electricity goes all goes...well I would refer to WW2. It seems that you can have a normal country and government with little food and electricity (eg Russia or UK)
All in all, climate change will undoubtedly hurt, but humans are much more adaptable than you would think. Witness the 2 world wars, or just the last one in Germany: everything was destroyed there and yet, after 20 years they emerged as a highly developed country again.
I am not saying that nothing is to be done - on the contrary, many things will have to change: what we eat, what we wear, how we travel, how we build our homes, etc, etc. This is happening. Yes, it should happen faster, I agree, but don't count out humans just yet!