Climate models and experts suggest surface waters in the
east-central Pacific Ocean are likely to be more than two degrees Celsius
warming than average, potentially making this El Nino one of the strongest
ever.
Typically, the warm air above the eastern Pacific is causing
increased precipitation over the west coast of South America and dry conditions
over the Australia/Indonesia archipelago and the Southeast Asia region, said
Maxx Dilley, director of the WMO’s climate prediction and adaptation branch.
Even though they have better prediction models, climate
scientists say it’s difficult to forecast the impact on Canada and the United
States because there is also an arctic warming effect at work on the Atlantic
jet stream current.
“The truth is we don’t know what will happen. Will the two
patterns reinforce each other? Will they cancel each other? Are they going to
act in sequence? Are they going to be regional? We really don’t know,” said
David Carlson, the director of the World Climate Research Programme.
This El Nino could also be followed abruptly by a cooling La
Nina, which, along with the advance of global warming, was adding to the uncertainty,
Carlson said.
“I think we all think that there’s some climate warming
signals starting to show up in the El Nino record,” he said.
But he added that it is still unclear how global warming has
affected the frequency or magnitude of El Nino events.
Since 1950, strong El Nino events occurred in 1972-3, 1982-3
and 1997-8. For the Prairies and central Canada, El Nino is usually, but not always,
linked to warmer and drier winters.