UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance ofan "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughtsand heavy rainfall to the rest of the world.THEWorld Meteorological Organisation (WMO) said its modelling suggested a"fairly large potential for an El Nino, most likely by the end of the second quarter of2014.""If an El Nino event develops ... it will influence temperatures and precipitation andcontribute to droughts or heavy rainfall in different regions of the world," WMOchief Michel Jarraud said in a statement.The El Nino phenomenon occurs every two to seven years, when the prevailing tradewinds that circulate surface water in the tropical Pacific start to weaken.WMO pointed out Tuesday that since February, trade winds had weakened and therehad been a significant warming of the waters below the surface in the centralPacific. "While there is no guarantee this situation will lead to an El Nino event, the longerthe trade winds remain weakened, and sub-surface temperatures stay significantlywarmer than average, the higher the likelihood," it said. Two thirds of climate models predicted that the phenomenon would beginsometime between June and August, with a few suggesting it could start as early asMay, and the remainder predicting no El Nino this year, it said. The last El Nino occurred between June 2009 and May 2010.It is often followed by a return swing of the pendulum with La Nina, which ischaracterised by unusually cool ocean surface temperatures in the central andeastern tropical Pacific.Scientists, who closely monitor the two climate patterns, say that while they are notcaused by climate change, rising ocean temperatures caused by global warming mayaffect their intensity and frequency."El Nino has an important warming effect on global average temperatures," Jarraudcautioned, stressing that combined with human-induced warming from greenhousegases such events had "the potential to cause a dramatic rise in global meantemperature.