Unstoppable forest fires in Canada. Dangerous heat waves in the southern United States, Europe, and North Africa. Higher air and sea surface temperatures that melt glaciers, ice caps, and ice sheets. Summer is in full swing in the Northern Hemisphere, accompanied by discouraging, and often disastrous, news headlines are heralding the impacts of a warming world.
In the next five years, the World Meteorological Organization warns of a 66 percent chance, or roughly 2 out of 3 odds, that Earth’s global temperature exceeds the 2.7-degree Fahrenheit (1.5-degree Celsius) above preindustrial levels benchmark. They also project a 98 percent likelihood that at least one of the next five years will see Earth’s warmest on record, which date back to around 1850.
Why is the hot weather happening? And why now? The answer lies primarily in the overlap of ongoing climate change and a naturally-occurring El Niño weather event that results from interactions between the ocean surface and the atmosphere over the tropical Pacific.
“The most important thing to remember is that the projected record temperatures we’re heading towards are the result of the combination of El Niño and climate change,” said associate scientist Dr. Christopher Piecuch, who studies sea level change in the physical oceanography department at Woods Hole Oceanographic Institution. In other words, we don’t “feel” climate change primarily through the slow and steady rise in sea levels, or increase in global temperatures. But rather, he said, through extreme events.
This could occur when a stronger, longer-lasting tropical cyclone drives storm surge on a higher baseline sea level, inundating and flooding more of an area than a weaker, shorter-lived storm a century ago would have, Piecuch said. “Or when a punctuated climate ‘event,’ like a strong El Niño, rapidly raises temperatures and effects weather globally and regionally on top of the ever-warmer planet we live on,” he said.
Meteorological forecasts suggest that the naturally-occurring warming event El Niño, switching from its cooler counterpart La Niña and more neutral conditions, will return in 2023, increasing global temperatures the year after it develops. The hottest year in recorded history, in 2016, was driven by a major El Niño event.
