Time has run out. Leading scientist David Keith has spent the past 30 years researching the controversial planet-cooling technology called solar geoengineering. It’s fast, it’s cheap, he knows for certain that it will work, and he’s ready to start. But as Al Gore put it, solar geoengineering is also “utterly mad.” As this powerful idea moves out of the lab and into a planet in the throes of a climate meltdown, it carries deep uncertainty. Part thriller, part wake-up call, PLAN C FOR CIVILIZATION reveals the hidden world of climate tech — and asks whether or not we can afford to ignore one of the most controversial ideas on Earth. Are some ideas too risky to explore, or is it time to turn to Plan C?