"The Bureau of Meteorology is shifting the way it communicates about climate phenomena such as El Niño and La Niña, because global heating is making predictions based on the past less reliable.

This week the bureau kept the country on a “La Niña watch” and said if the climate system in the Pacific does develop, it’s likely to be short-lived and weak.

Historically, La Niña events – where warmer waters gather to the north of Australia – have been associated with cooler and wetter conditions from across north-western Australia to the south-east. El Niño events are often warmer and drier.

But Dr Karl Braganza, national manager of climate services at the bureau, said climate change and the amount of heat being added to the oceans made those old relationships less reliable.

Climate change may not have “broken” them, he said, “but the number of times when the climate is inconsistent with what we saw in the past will only increase”…