Ridley states, "Nowadays, because of world trade, it's pretty well impossible to have a major global famine. It could only happen if there were simultaneous droughts in many different parts of the world....So trade has reduced the risk by linking us all up. Some people say we've made the world more risky by connecting everyone. That may be true in some cases but not all of them. In a lot of other examples, it's actually enabled us to spread risk to reduce it" (37). What does Ridley mean?