Possibly because I have studied this for 50 years, and the people who write all these solutions come from western nations. Americans are only 5% of the world's population, and they are not taking into account the rest of us.

Nor do they take into account human behaviour. A recent UN poll showed that while everybody wanted government to resolve climate change, people weren't willing to change their behaviour.

Konstantin Kisin pointed out something quite significant - that the poor of the world would not change their behaviour, e.g. burning fires to keep warm, using oil, peat, etc. They didn't have the money to invest in the 'green tech' of the first world.