How is El Nino affecting countries around the world?

Powerful hurricanes in Mexico, drought in Ethiopia, flash-floods and mudslides in southern California - all have been attributed to the El Nino weather phenomenon.

Occurring every few years, the current El Nino is one of the strongest recorded and could contribute to making 2015 the hottest year on record.

But what is El Nino?

BBC Weather's Nick Miller reports.