Global disruptions from the war in the Middle East are forcing a rethink of what truly threatens the world’s food supply. While climate change has long dominated the conversation, there is a far more immediate and practical vulnerability: access to the energy resources that modern agriculture depends on. Artificial fertilizers account for 50 percent of all the calories we consume, and they rely heavily on natural gas. Without fossil fuels, half the global population would suffer from severe food shortages. The war in Iran and the blocking of the Hormuz Strait are not just driving up global energy prices. Crucially, a quarter of the world’s fertilizer normally passes through the strait, and the blockade is holding back much of the fertilizer needed to grow the food that will feed the world in the coming year. The United Nations estimates that this could drive up fertilizer prices 15 percent to 20 percent and push at least 45 million people into acute hunger.…