El Nino will be the worst in over 15 years: UN warns ‘severe’ impact of weather system will be felt throughout the world The 'El Niño' weather system, which sparks global climate extremes, is this year set to be the worst in more than 15 years. This is according to a UN weather agency, which today warned that El Niño is already causing severe droughts and flooding across the world. The World Meteorological Organisation said El Niño, which occurs every two to seven years, had resurfaced a few months ago. WHAT IS EL NIÑO? El Niño is caused by a shift in the distribution of warm water in the Pacific Ocean around the equator. Usually the wind blows strongly from east to west, due to the rotation of the Earth, causing water to pile up in the western part of the Pacific. This pulls up colder water from the deep ocean in the eastern Pacific. However, in an El Niño, the winds pushing the water get weaker and cause the warmer water to shift back towards the east. This causes the eastern Pacific to get warmer. But as the ocean temperature is linked to the wind currents, this causes the winds to grow weaker still and so the ocean grows warmer, meaning the El Niño grows. This change in air and ocean currents around the equator can have a major impact on the weather patterns around the globe by creating pressure anomalies in the atmosphere http://www.dailymail.co.uk/sciencetech/article-3320959/El-Ni-o-worst-15-years-warns-severe-impact-weather-felt-world.html