The chances of an El Niño, the global climate phenomenon that can destroy crops in Asia and offer a relief from harsh winters in North America, were raised to 70% on Thursday. But scientists said the coming El Niño was likely to be of only moderate strength.

In their monthly forecast, scientists from the US government's Climate Prediction Centre said warming sea temperatures in the Pacific continued to create the conditions for an El Niño this summer.



“The chance of El Niño is 70% during the northern hemisphere summer and reaches 80% during the fall and winter,” the centre said. Its ultimate strength had weakened over the last month. “Regardless, the forecasters remain just as confident that El Niño is likely to emerge,” the forecast said.

There has been growing anticipation of an El Niño this year – because of its widespread impacts.

In California, there has been hope that a strong El Niño could be a drought buster. The phenomenon is known for bringing wetter winters to Texas and southern California. They are also good news for Florida and the Caribbean, damping down the hurricane season in the Atlantic.

But El Niños can wreak havoc on fisheries in South America, and worsen droughts in part of Asia, Africa, and Australia.



That type of El Niño, with widespread global impact, has yet to fully materialise, the scientists said. While warmer sea temperatures in the Pacific were building conditions for an El Niño, the scientists said they were still not seeing the inter-action with atmosphere they would expect for a really big event.



“We are slightly favouring a moderate strength El Niño. While we are not ruling it out at this point, we are not expecting to see the next great El Nino,” said Mike Halpert, acting director of the Climate Prediction Centre.



Independent climate scientists said they too were expecting one of only moderate significance.



“We are going to have an E Niño. The question is the strength,” said Kevin Trenberth, a climate scientist at the National Centre for Atmospheric Research. “It hasn't taken off in the last month the way one might have thought if it was going to be a really major event.”



There was still time for a stronger El Niño to develop, however. It typically continues to develop over the summer months.



“We are on the precipice of actually having it here. The ocean has reached the minimum temperature but we are waiting to see the interaction with the atmosphere,” Halpert said. “It is certainly within the realm of possibility that it does become a very strong event but it would take some interaction with the atmosphere that we are not seeing right now.”

