El nino and la nina: children of the tropics -- What causes el nino and la nina? -- The global effects of el nino and la nina -- El nino and la nina effects on climate in the United States: winter and spring -- ENSO and summer weather patterns -- Other effects of ENSO -- How scientists study El Nino -- Forecasting ENSO -- The super el ninos -- How governments use ENSO-based seasonal forecasts -- ENSO, tip of the iceberg in climate prediction.