Forty Signs of Rain is a lightweight eco-thriller. The principal characters are climate scientists working in Washington DC and San Diego while the climate gradually worsens. The time-scales are short enough that it isn't plausible to treat the increasing storms as more than anecdotes, but they're big enough (the mall in Washington DC floods because of a combination of high tides and storms feeding both watersheds that drain into the Potomac) to be striking to most readers. The kind of striking image that leads people to reasoning from fictional evidence.'s
But the story is engaging, the characters are plausible examples of the stereotypical focused scientist. Many loose ends are left hanging to the sequels. The only science fiction seems to be the speed of onset of global warming. There are several scenes involving start-up biotech firms, and the politics of recruiting. There's also a significant amount of time spent in Washington, both in giving grants to scientists, and lobbying congress to do something about the state of the world. It all rings reasonably true, and will be familiar to anyone who has worked in technology, academy, or government.
One of the characters is an ex-rock climber. I didn't find anything discordant in any of the climbing scenes. I've even been involved in rappelling into a building atrium (not solo, though) and found that description plausible as well.
Fun, but not deep. The whole purpose seemed to be to show us a powerful vignette of the effects of global warming, and I'll admit that the image is powerful.