Temperature records show that the Earth has warmed a little more than 1 degree Celsius (2 degrees Fahrenheit) since 1880. Yet short-term variations in weather, such as cold snaps — rapid drops in air temperature that result in consecutive days of colder-than-average weather — are still occurring.
To understand how record-cold events can exist in a warmer world, consider an event from winter 2018-2019.
In January 2019, a cold air outbreak swept across portions of the Northern Plains and Midwestern United States. Temperatures plunged below minus-40 degrees Fahrenheit, with wind chills in the neighborhood of 60 degrees below zero. However, despite this bitter cold snap, the nation’s average temperature for the month was nearly three degrees Fahrenheit warmer than normal. January 2019 was also the globe’s third-warmest January on record.
How is that possible? Well, while a few U.S. regions were experiencing record-breaking cold, above-average warmth was occurring in other parts of the country and the rest of the world. For example, January 2019 temperatures across the western United States ranged from three to nine degrees above the normal January average, while in Australia and Asia, temperatures were seven degrees or more above normal.
Such situations exemplify how cold snaps and global warming can and do coexist: Cold extremes are occurring over a smaller fraction of the global surface area than above-average temperatures. In other words, what happens locally, or over short periods of time, is not necessarily representative of what’s happening nationally and globally.
Speaking to the Washington Post, Jason Furtado, assistant professor of meteorology at the University of Oklahoma, explains it using this widely used analogy: “One down day on the Dow Jones doesn’t mean the economy is going to trash. (Likewise) one cold day doesn’t suddenly mean that the general trend in global climate change is suddenly going in the opposite direction.”
Carl Schreck, atmospheric scientist at North Carolina State University’s North Carolina Institute for Climate Studies, agrees. “Cold snaps don’t disprove global warming,” he says, “they just mean that weather and seasons still happen.”
