El Niño and La Niña are swings in Pacific Ocean temperature that change rainfall, heat and storms around the world. Forecasters use physics-based models that begin from present ocean and atmosphere conditions and simulate months ahead. Long-range forecasts are hard because of chaos: in the 1960s Ed Lorenz showed that a tiny change in starting conditions can drastically alter a model's results, which limits weather forecasts to a week or two. But El Niño is driven by the slow-moving ocean, which is more predictable. A new study suggests some El Niños can be predicted up to 12 months ahead, versus about June for the current one, the earliest reliable warning today. The present El Niño is strong and has already been linked to floods in eastern Africa, European heatwaves and eastern Pacific hurricanes.

In 1909 D. W. Griffith made a 14-minute film about a speculator who corners the wheat market and doubles the price of bread. A farmer sows his field while a 'Wheat King' gambles in the Chicago wheat pit; bakers raise the loaf from five cents to ten and the poor line up for bread. Griffith cut back and forth between the farm, the feast and the breadline, a technique called parallel editing, so audiences saw both ends of the economy at once. The film drew on Frank Norris's stories and on a real scheme: months earlier Chicago financier James Patten had cornered wheat, sent bread prices up and made about $5 million, roughly $185 million today.