When it gets hot — or cold — this summer, don’t blame the kid.
Detroit’s recent swing from hot and dry to cold and rainy was unusual, but it can’t be pinned to El Niño (Spanish for “the child”), a global weather pattern that can lead to warmer, dryer weather in the upper Midwest, particularly in the winter.
Forecasters declared last week that an El Niño cycle is underway and that there’s a pretty good chance — 56% — it will be a strong one. The cycle could give us a noticeably warmer winter in Detroit, but its summer effects in the midwest are mild. If we get a hot Detroit summer, other factors, such as heat waves linked to global warming, will be the more likely culprit.
El Niño and Detroit
Together with its mirror image — La Niña — El Niño is the globe’s strongest year-to-year weather pattern. This planetary chain reaction is kicked off by a shift in trade winds all the way in the Pacific Ocean, which moves masses of warm seawater away from their usual location and fuels extreme weather in every corner of the map. A particularly strong El Niño cycle in 2015-16 was linked to flooding in Indonesia, drought in southern Africa and record bleaching of Australia’s Great Barrier Reef.
In Detroit, the effects of El Niño are relatively mild. Especially in a strong El Niño year, we can expect a warmer, drier winter.
The effects are less stark in the summer. Midwestern summers before an El Niño cycle (like this year) are typically slightly cooler than usual, according to the Midwestern Regional Climate Center at Purdue University. The cycle reaches full strength in winter, and then the following summer tends to be slightly hotter than average.
Those small effects can be overridden by other factors, however. That’s one reason El Niño is sometimes compared to a bad bartender who occasionally brings the wrong drink.
“The summer outlook is actually for equal changes of above or below normal temperatures,” said Dave Kook, a meteorologist for the National Weather Service in Detroit. “And that takes into account many factors, more than just the current state of El Niño.”
It’s still unclear whether human-caused climate change will lead to stronger and more frequent El Niño cycles, but there’s no doubt they are a nasty one-two punch. With global warming well underway, a powerful El Niño helped make 2016 the hottest year in human history.
A strong El Niño this winter could put 2023 in the running.
One fix for heat: Plant more trees
Even an average summer in Detroit would have its share of dangerous heat. Heat is nothing to scoff at, especially for older residents and those with medical conditions. An estimated 47% percent of Detroiters lack central air conditioning, leaving thousands vulnerable to heat stroke and dehydration, even though cooling stations are available on especially hot days and some neighborhoods are organizing resources to help citizens during a heat wave.
Trees can help reduce heat, pushing down air and surface temperatures in neighborhoods with dense canopies.
Planting an estimated 14,000 new trees each year for the next two decades would be enough to help Detroit ensure that low-income people of color aren’t trapped on damaging “heat islands.” But the city has struggled to hit that target. The city has not planted trees quickly enough to make up for regular die-off and the destructive effects of pests like the emerald ash borer.