In November 2015, David Phillips, senior climatologist for Environment Canada, spoke to Canadian Geographic about the ongoing 2015-16 Super El Niño.
How do you tell an El Niño from other climate patterns?
El Niños have a particular signature. They begin around the same time, in spring, and die out approximately nine months later (although some fade and then return).
We know that for an El Niño to happen — especially a Super El Niño — the equatorial Pacific’s trade winds have to have switched direction, pushing warm waters east from Indonesia for months until they’re sloshing along the west coast of South America. That measurably warmer water heats up the atmosphere, causing more instability — storms here, lows over here, highs over here. That’s why you get that persistent El Niño weather: highs result in droughts, lows bring heavy rain.
How can meteorologists be so certain about a long-term forecast?
Unlike the weather, which can be here today and gone tomorrow, El Niño is going to be there tomorrow, next month, next season, and maybe the season after. Those warm waters stay put, and that’s the key thing.
The “El Niño index” that we look at to gauge the strength of the temperature anomaly is essentially driven by the temperature of the sea surface [to be considered an El Niño year, sea-surface temperature must be at least 0.5 C warmer than the long-term average]. When the waters warm up, the winds are also affected — although that’s kind of a chicken-or-the-egg situation. But that’s the coupling we look for; the advances of the ocean have to be either accepted or spurned by the atmosphere.
Meteorologists use the index to categorize the systems as super, moderate or weak compared to past El Niños. And of course, the more “super” it is, the higher the likelihood that you’ll get those dramatic atmospheric impacts.
So this is about as certain as a weather person can be about anything?
We can never guarantee how El Niño will affect us, or affect anywhere, but that’s right. We’re confident this is not going to go away. There could be days when [its warming effect] will relax, and cold air will come down from our Arctic, and then El Niño will return and push that cold air back up. But if you come back to me in a month for more information, the El Niño will still be there. It generally peaks about December or January. It wanes in spring and has pretty well disappeared by summer. We’ve known El Niños to go on for two years, but all the models seem to suggest that this one will be dissipating by the spring. Climatologists are already comparing it to the Super El Niños of 1997-98 and 1982-83, but whether it becomes as large as that, or becomes the second or third warmest of seven, remains to be seen.
What can North Americans expect?
There’s been a lot of buzz worldwide about this El Niño since March or April , and it’s only become progressively warmer. El Niños tend to create extreme weather. You go from almost flooding situations to drought situations — nothing in between. That’s why it can be a real bad boy. Whatever you get, there tends to be too much of it. There were heavy rains and flash floods in Texas and the Gulf states in November and October, and California has seen rains and landslides, which also might be an early impact. (Even the droughty ground, like they have in western North America right now, cannot take flash floods.)
Here in Canada, it’s generally characterized by a milder-than-normal winter. That can be good or bad news for people. Skiers in some regions might not benefit, while it could save many people on their heating bills.
How are other places in the world being affected?
[As of early December 2015] A full accounting of this El Niño’s effects are not known yet, and it’s important to sort out previous and current effects, and El Niño impacts from other weather that’s not driven by those warm waters.
But what is known at this time is that there are few surprises. The North Atlantic Ocean will end the tropical storm season quietly, with few hurricanes but near-normal tropical storms. The eastern Pacific, meanwhile, has had a very active tropical storm year. We’ve seen powerful hurricanes, including the biggest one ever — Hurricane Patricia. That is fallout from El Niño.
The dry and heat underway in southeastern Australia has an El Niño signature: drought. I saw a recent statistic that of 26 El Niños recorded there since 1900, 17 have resulted in widespread drought. Southeast Asia has had below-normal and spotty rainfall, which has reduced reservoir levels to critically low levels. The smoke in Singapore is worse this year thanks to a lack of rains to snuff out the fires, and there are more fires burning in Sumatra, Borneo and New Guinea for the same reason.
Are there other “weather makers” that could overtake the 2015-16 El Niño?
Many people assume that an El Niño year automatically means a warmer Arctic, but this is something that has thrown us every Super El Niño so far: never once have we seen a related disappearance of ice from the Earth.
So Canada’s Arctic waters, up there at the top of the world, could certainly have an influence on how this plays out. In El Niño years, the jet stream blows strongly from west to east, and even though it’s warm air, it tends to push the cold air further north, where it belongs. Nevertheless, if winds blow steadily from north to south, you can bet that Arctic air could for a time diminish the apparent warming effects of El Niño.
There’s no science that has established that exchange other than the fact that we know the shape of the jet stream. But that it’s providing a bit of uncertainty is like breaking news. By the time people read this in Canadian Geographic, they could well be asking, “Where is that El Niño when you need it?”