France, May 25 -- El Nino is a natural climate pattern that develops in the Pacific every two to seven years and can disrupt weather around the world, bringing drought to some regions and heavy rain to others.

Forecasters at the US National Oceanic and Atmospheric Administration (NOAA) say there is about an 80 percent chance of El Nino developing by July.

Sea temperatures in key parts of the equatorial Pacific are climbing quickly, while a large pool of unusually warm water is building beneath the surface.

Several weather services predict Pacific temperatures could rise by 2.5C or more above average later this year. Only three El Nino events since 1877-78 have crossed the 2C mark, in 1982-83, 1997-98 and 2015-16.

"There's definitely s...