El Nino in its simplest terms, is the unusual warming of ocean waters, primarily in the Pacific Ocean near South America. Its cause is mostly unknown by scientists. An El Nino event usually happens once every 3-7 years in December.
The effects of El Nino and La Nina on ocean temperature (Red and White indicate high temps, blue and purple are lower temps.)
The warmer waters can be beneficial to fish populations and are often welcomed by fisherman. However El Nino and its opposite La Nina (cooling of ocean waters) can be destructive causing heavy rains, droughts, destruction of marine life, and typhoons all over the world.
Bibliography
Sources
1.http://www.ucar.edu/communications/factsheets/elnino/
2.http://www.esrl.noaa.gov/psd/enso/enso.description.html
Images
1. ciesnce.nasa.gov/.../el-nino-la-nina_med.jpg
2.apod.nasa.gov/apod/image/9801/elnino4_jpl_big.jpg
