The literature suggests there is ~ 0.3% chance per year of full-scale nuclear war. This event would have ~ 20% probability of causing U.S. mass starvation due to collapse of conventional agriculture from smoke blocking the sun. Alternate foods exploit fossil fuels(e.g. methane digesting bacteria) and stored biomass (e.g. mushrooms growing on dead trees) and are technically capable of saving all Americans from starving. However, current awareness is low and the technologies need to be better developed. This Monte Carlo study investigates the economics of three interventions including planning, research and development. Even the upper bound of $20,000 per life saved is far lower than the millions of dollars typically paid to save an American life. Therefore, it should be a high priority to implement these interventions as they would improve American resilience and reduce the possibility of civilization collapse.
Available at: http://works.bepress.com/jmpearce/205/