（四）The climate phenomenon known as El Nino(厄尔尼诺）seems to be on its way back, forecasters say, raising the possibility of droughts in some places and floods in others. El Nino occurs every few years, when tropical waters off the Pacific coast of South America turn warmer than normal. Warm air rises off those waters and changes the path of the major wind currents that blow around the planet. It can weaken monsoons(季风）in South and Southeast Asia. Rainy seasons in southernAfrica can turn dry. Meanwhile, East Africa and South America can get soaked.The latest official forecasts say that there are early signs that El Nino could develop into the biggest one on record. What has attracted attention is the huge body of warm water building up below the surface of the tropical Pacific. Experts say there is more energy stored up underwater now than at this point in 1997, just before the strongest El Nino on record developed. If those warm waters in the eastern Pacific make their way to the surface and stay there, it could mean a major El Nino event, extreme weather worldwide and possibly new high-temperature records.However, just having a lot of warm water below the surface now is not enough to guarantee that we're going to have a strong El Nino. The warm water could dissipate (消散）. It could come to the surface but not stay. Plus, the atmosphere has been in a cooler cycle for the past several years, which many say does not favor a strong El Nino.16. What predictions do experts make about El Nino?

A. It may develop into an unprecedented scale.
B. It will go hand in hand with floods and droughts.
C. It may bring disasters to the Pacific coast of South America.
D. It will worsen the world climate warmed by carbon dioxide.