Here's a helpful (i.e. simple) video that illustrates El Nino and La Nina events and the role they play in climate change. Recent studies predict the El Nino Southern Oscillation (ENSO) will be getting stronger and the events more frequent. We have also learned that, of late, unusually powerful Trade Winds have been transferring heat from the atmosphere into the depths of the Pacific Ocean.
The first couple of minutes of this video deal with the difference between climate and weather but the ENSO discussion begins at the 2:40 mark. It's a dandy little vid you might want to forward to your grumpy old uncle.