El Niño means “little boy” in Spanish because the phenomenon appears around Christmas. It occurs in the Pacific Ocean. Every few years, the temperature of the normally cool surface waters of the eastern Pacific Ocean increases, lasting for several months. In turn, the warmer waters affect the atmosphere, and rainfall and surface temperatures increase substantially.
El Niño is known to have caused drought and even forest fires in Australia, Indonesia and in parts of South America, but also weaker summer monsoon in South Asia, among others. In addition, El Niño is also associated with heavy rainfall and floods in parts of eastern Africa. However, not all instances of unusual weather during an El Niño can be attributed to it. Regional and local conditions can make El Niño’s potential impacts worse, or can block them from happening.
Questions and Answers
When storms, hurricanes, droughts and floods happen, humans are threatened, WMO and National Meteorological and Hydrological Services help to protect people by providing early warnings. WMO, through special international centers, does research for better understanding the El Niño phenomenon. The organization regularly issues El Niño/La Niña updates based on a consensus of a worldwide network of climate experts, providing authoritative early warning of the phenomena.
La Niña, which means “little girl” in Spanish, is characterized by unusually cold ocean temperatures in the eastern Equatorial Pacific Ocean. El Niño, in contrast, is characterized by unusually warm ocean temperatures in the same area. The effects of La Niña tend to be opposite those of El Niño. For example, Australia and Indonesia are wetter than normal during a La Niña event, and the Asian summer monsoon is stronger than normal. Increased hurricane activity can usually be expected over tropical Atlantic Ocean during a La Niña event, but it is inaccurate to say that an individual storm is La Niña induced.