(I kept putting off this because I hadn't quite worked out what I wanted to say. It is apparent now that I don't know).
Anyhow, number three in the climate change series. It's good.
It's an odd combination of disaster story (i.e. what will happen if we fail to act) and optimistic one (i.e. we can save ourselves, if good people make the effort). Plus there's some basic family and romantic drama for the main characters.