The share of incomes spent on staples is about to jump everywhere. ( The Economist ) In October 1914 the Ottoman Empire, having just joined the first world war, blockaded the Dardanelles Strait, the only route for Russian wheat to travel to Britain and France. The world had entered the conflict with wheat stocks 12% above the five-year average, but losing over 20% of the global traded supply of the crop overnight set food markets ablaze. Having risen by a fifth since June 1914, wheat prices in Chicago, the…