Toronto Star: The warning bells are ringing, furiously. This week, food riots paralyzed Haiti, with angry marchers outside the president’s palace shouting “We are hungry!” Five people were killed in the chaos. In Egypt, a 15-year-old boy was shot and killed this week in two days of violence over food shortages. Last month, a two-week protest at government-subsidized bakeries ended with the deaths of 10 Egyptians in clashes with police. Rice is the staple food of 4 billion …