Then you actually need to be able to say something about how climate change will influence El Nino, and by studying the past relationship between El Nino and natural factors
like volcanic eruptions we could potentially better inform our understanding of how the El Nino
phenomenon will respond to climate change.
Their causes range from completely unpredictable events
like volcanic eruptions (which have mainly local effects) to more regular
phenomena such as «El Niño» (a warming of the surface waters of the tropical Pacific that occurs every three to five years, temporarily affecting weather world - wide).