The impact of the current El Nino cannot be predicted due to the complicating factor of climate change, according to the World Meteorological Organisation (WMO).

Damage has already been done across the world, from haze-producing forest fires in Indonesia to tropical cyclones in the western North Pacific and eastern North Pacific basins.

The Australian bushfire season has started early following an unusually warm and dry spring in many areas.

The WMO says the world is better prepared than before, but nobody knows quite what is coming.

“Our scientific understanding of El Nino has increased greatly in recent years,” Secretary-General Michel Jarraud said.  “However, this event is playing out in uncharted territory.

“Our planet has altered dramatically because of climate change, the general trend towards a warmer global ocean [and] the loss of Arctic sea ice and more than 1 million square kilometres of summer snow cover in the northern hemisphere.

“So this naturally occurring El Nino event and human-induced climate change may interact and modify each other in ways we have never before experienced.

“Even before the onset of El Nino, global average surface temperatures had reached new records. El Nino is turning up the heat even further.”