The effects of El Niño Southern Oscillation, ENSO or El Niño for short, include stronger eastern winds which bring more rainfall, storms, and flooding during the summer months, typically followed by unusually warm, dry winters. Countries that rely on agriculture or fishing to make a living may suffer losses during El Niño due to the extreme weather and the fish dying or moving to cooler areas. Due to the stronger eastern winds created by El Niño, hurricane season in North America is often less severe.
Parts of South America strongly influenced by the effects of El Niño experience wet winter seasons with a high chance of flooding. Long periods of El Niño weather cause a shift in the agriculture and fishing industries, especially in countries such as Peru. Crops and local fish may suffer from the sudden change in the weather pattern.
In North America, winters are drier than normal in the northern parts instead of wetter as they are in South America. Lower North America experiences wetter winters since it lies closer to the equator, the most affected region in the Pacific Ocean. The strong east-to-west winds reduce the hurricane season for much of North America. In Australia, however, dry conditions typically occur and can lead to an increased number of wildfires.
El Niño occurs when tropical eastern areas of the Pacific Ocean become warmer than usual by 0.9 degrees Fahrenheit (0.5 degrees Celsius) or higher, causing stronger winds coming from the east and lower air pressure over the ocean. This change in temperature and air pressure causes the ocean water to rise higher than normal. When the opposite effect happens — the water temperature drops instead of rises — this is known as La Niña. Weather patterns opposite those experienced during El Niño are common in affected countries during La Niña.
Scientists are unsure what causes El Niño, but estimate it occurs every three to seven years. When a dramatic shift in temperature and air pressure occurs, the weather disturbance caused by the effects of El Niño is quite high. Countries may experience drought or flooding and a shift in normal temperatures for the season.
Known as a climate pattern, El Niño is a weather pattern that reoccurs over a time. Studying El Niño can help better understand why it occurs and predict when it will occur again. Advanced warnings can help countries prepare to deal with the effects of El Niño.