Tempted to joke about global warming amid a blizzard? Here's what experts say about that.
- Cold, wintry weather might make global warming seem like less of a threat or something to joke about.
- But cold winters still happen as the planet warms.
- Data shows how winters are getting warmer, but that doesn't make cold weather go away entirely.
Climate change is real despite winter storms, snow and cold. But when -50 degree windchills are in the forecast, global warming may seem to some like less of a threat — or maybe even something to laugh about.
Just like clockwork, the emails, tweets and Facebook posts start flowing during the winter.
Maybe it's a joke, maybe it's a snarky critique, maybe it's a meme. The words change, but the format is familiar: If global warming is real, why is it so cold out?
We asked experts to weigh in on the winter weather trope. Here's a few thoughts on what winter means in an era of global warming.
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Cold winters don't mean there's no global warming
Atmospheric science professor Dan Chavas at Purdue University in Indiana says these arguments don't frustrate him because they're a chance to engage.
"I think most of the time when people say that, they are joking and do not seriously believe that the occurrence of winter disproves climate change," he said. "For me personally as a scientist, I see that type of comment as a potential opportunity to talk about climate, the seasons, and climate change if they seem interested."
He starts that conversation by agreeing that climate has always had seasons, but notes climate change is a gradual warming – on top of the seasons – that's making winters, springs, summers and falls all warmer over time.
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Higher temperatures don't mean it's hotter everywhere all the time
Global temperatures have risen 1.9 degrees Fahrenheit since 1880. That doesn't mean it's hotter everywhere all at once but that the entire system is becoming more volatile.
"As you add energy to the system, both extremes grow. You can have Texas ice storms as well as 33 million people displaced in Pakistan due to heat and flooding," said Julio Friedmann, chief scientist at Carbon Direct, a carbon-management firm and a former professor at Columbia University. "These sorts of changes were predicted in 1996, it's not news that this is happening."
That said, winters are indeed getting warmer.
Since 1896, average winter temperatures across the lower 48 states have increased by nearly 3 degrees, according to the Environmental Protection Agency. Nationally, 57% of US Weather Service stations have shown a decline in snowfall since the 1930s.
Winter weather is now on average 14-and-a-half days shorter and summers are seven and a half days longer, according to Brian Brettschneider, a climate scientist with the University of Alaska at Fairbanks
"Global warming will not stop the seasons, but it is causing long-term trends in winter conditions that are robust and accelerating," said Jason Smerdon, a climate physicist at Columbia University.
The odds are shifting to hotter extremes
But climate change is never all one thing or another. Rather it is a shift in the odds of occurrences of extremes, said Gerald Meehl, a senior scientist with the National Center for Atmospheric Research.
Over the U.S. during the past decade, it is twice as likely that a daily record high maximum temperature occurred at a given location compared to a daily record low minimum, he said.
"For every two daily record high maximums that are set, there is only one daily record low minimum. This is climate change happening before our eyes," he said. "If the climate wasn't warming, there would be an equal chance of a daily record high temperature being set compared to a daily record low minimum."
Over the rest of this century, the number of extreme heat events will rise, even though there are a few extreme cold events.
"I've said that the scientist sitting at my desk in the year 2100 will get a phone call on a cold day in January 2100 when a daily record low minimum temperature is set in Denver," he said.
That caller will want to know what happened to global warming because a record cold temperature has just been recorded.
"That scientist in my seat will answer that yes, it was cold on that one day," he said. "But think back to the previous summer when nearly every day set a daily record high maximum temperature.