Over the last few decades, we have heard about El Niño and La Niña. But what are the difference between El Niño and La Niña? First of all, I have to tell you that even now scientist are not 100% sure why they happens. But most of the scientists agree that it is somehow related to global warming, and they are caused by certain types of special waves. Both El Niño and La Niña will make the weather from a series of places temporarily up side down. For example the dry places become rainy while the humid places become extremely dry. This serious affect our agriculture. Places that are suitable to plant rice becomes too dry to plant any and places that are used to be suitable for finshing becomes no good. El Niño usually occurs in tropical waters of the Pacific Ocean every 2 to 7 years, and it affects the region across the Pacific from New Guinea to South America, known as the Equatorial Pacific. When it happens, a series of complicated changes in ocean currents and winds brings warm water in a westerly direction, displacing the usual cold water that comes up from the ocean depths. The fish that lives there has to move because of such a temperture change, and their breeding season is interupted. Oppositely, La Nina usually occurs in the central and eastern tropical Pacific (roughly the same place where El Niño occurs) making the surface of ocean cooler than normal conditions. Again, it changes the weather a lot and makes things up side down. Not only the weather is affected, unlucky things happens to the lovely fish in the ocean again. What is worse is, this phenomenon can probably last up to a year!!! (the same to El Niño) So it is easy to remember: El Niño makes ocean surface warmer, and La Nina makes coean surface cooler! That's the trick for multiple choice questions!