What insurance can the world afford to prevent repeating the catastrophic temperature increase of the past? A package of fast mitigation measures is recommended by Nobel Laureate Mario Molina and colleagues Durwood Zaelke, K. Madhava Sarma, Stephen O. Andersen, V. Ramanathan, and Donald Kaniaru. These fast-action mitigation measures can be implemented in two to three years and produce climate benefits in one to two decades. They complement efforts to cut CO2 under any climate treaty.