CORAL fossils in the Pacific Ocean show the El Nino weather pattern is not influced by climate change.

Researchers sampled fossil corals from Christmas and Fanning Islands in the tropical pacific and found there was no clear trend in El Nino's behaviour during the past 7000 years.

Researchers at the Georgia Institute of Technology in Atlanta, US, wondered whether El Nino, which occurs about every five years and has a massive impact on the weather, would become more or less variable due to climate change.

Georgia Tech found while El Nino's behaviour is more variable today than in recent history, it is not unprecedented and a link to global warming is difficult to prove.