Timescape

Timescape - Gregory Benford

Reread this one recently.
Published in 1980, it is a time travel story (of sorts), where a team of scientists in 1998 attempt to send messages to 1962 so mankind avoids certain global actions that cause an enviromental collapse in their time.
The catch is they have to avoid the grandfather paradox; they want to avoid the enviromental collapse, but without changing history so much that they eventually don't send the message back in time.
Considered "hard" sci-fi, the story sometimes plods along, and there is no climax to the story in itself, until the very end.

3 out of 5