Within two years, atmospheric sulfur levels plunge to pre-geoengineering levels, and the global average temperature, artificially suppressed for a decade, comes roaring back. Once again, patterns of precipitation and temperature shift abruptly, wiping out the efforts of the world's farmers to adapt to the changes of the decade prior. The high temperatures free billions of tons of methane—a greenhouse gas 30 times as potent as CO2—from the melting Arctic permafrost, which in turn accelerates warming. The process becomes self-reinforcing and unstoppable. By 2050, starvation, disease and near-constant armed conflict have devastated the developing world. India and Pakistan, starving, desperate and paranoid, are on a nuclear hair trigger. Then a bomb goes off in India, and things really start going badly.