Every 3 to 6 years, normal weather conditions around the world are disrupted.
Oceanic currents change, causing a shift in sea temperature, wind direction and rainfall patterns.
This is the phenomenon known as El Ni o. Some areas that are usually dry receive lots of rain. Other areas that are normally wet go through a dry spell. After a period of about a year the cycle switches and La Ni a takes over bringing the opposite climatic conditions . Such extreme weather usually receives a bad press but now Dutch scientists have written favourably about the phenomenon in a recent edition of the popular science magazine New Scientist .