Feel Like Spring Arrives Earlier Today Than It Used To? That's Because It Does

By Terrell Johnson
Published: March 20, 2014

Despite winters like this year's, which has brought weeks-long periods of frigid air and dumped multiple rounds of snow across the eastern United States, the start of spring is slowly but surely moving earlier on the calendar with each passing year, proof that Earth's warming is leaving its footprint on a wide range of climatic signals.

"It has been a brutal winter" across the eastern half of the U.S., where temperatures have averaged 5 to 7 degrees below normal for the season, said Dr. Michelle Thaller, a scientist with NASA's Goddard Space Flight Center, in an interview Thursday.

"But if you actually look at a global perspective, it's been a warmer-than-average winter," she said. "In the western U.S. and across Europe, it's been quite a warm winter. It's a very good demonstration of the difference between weather locally and long-terms trends in climate."

(MORE: Spring Is Here, But When Will It Feel Like It?)

Since the 1950s, the date of winter's last frost – which usually occurs sometime in mid- to late March – has been creeping farther north, and now occurs about five days earlier than it used to across most of the U.S.

That has left places known for a particular climate feeling a lot more like their counterparts much further south, according to Dr. Compton Tucker, a senior scientist at NASA.

"The analogy I use is ... as if Winnipeg moved to Minneapolis-St. Paul over 50 years," he said, noting a Canadian and American city separated by more than 450 miles. "The onset of spring in Winnipeg now occurs like the onset of springs in Minneapolis-St. Paul in the 1950s."

A pair of recent studies bolsters this claim. Last year, a study in the journal Nature Climate Change found that temperature seasonality – the difference between summer and winter temperatures – is growing narrower over time, especially in areas above the U.S.-Canadian border.

(MORE: The Science Behind the Vernal Equinox)

And another study published in 2012 found that the experiments researchers use to mimic the effect of warmer temperatures on plants – which are used to forecast how plants will respond to future climate change – actually under-predict real-world warming by a large margin.

How do we see that unfold on the ground? Plants leaf out and flower earlier than they used to, snowpack melts sooner than it used to, birds migrate at different times, and insects like the bark beetle can invade forests for longer periods, allowing them to do more damage.

"There are parasitic insects, the more frost-free days you have, the more they can take hold," said Dr. Thaller. And because warmer temperatures are melting snowpack sooner in the year, she added, the ground dries out later in the summer – which makes for optimal conditions for wildfires.

"We may be looking at a bad wildfire season in the American West," she said.

“The case of spring coming earlier, this is in fact a long-term trend that we’ve observed," she added. "There are far-ranging consequences, even to a small shift in climate."

 

MORE: Spring Allergy Myths

Top 10 Spring Allergy Myths and Mistakes (Credit: Thinkstock)


Ad Blocker Enabled

Featured Blogs

Darby Falling Apart as it Makes Landfall on Hawaii's Big Island

By Dr. Jeff Masters
July 23, 2016

Tropical Storm Warnings are flying for the Big Island of Hawaii, Maui and Oahu as Tropical Storm Darby dashes itself against the high mountains of the Big Island. Saturday evening satellite loops showed that Darby was becoming misshapen and disorganized as it made landfall on the Big Island, and radar on the Big Island showed a highly asymmetric storm, with all of the heavy rains confined to the southeast side.

Hottest Reliably Measured Air Temperatures on Earth

By Christopher C. Burt
July 22, 2016

As Jeff Masters mentioned in his recent blog, a temperature of 54.0°C (129.2°F) was observed at Mitribah, Kuwait on July 21st. According to the Kuwait Meteorological Department this was the hottest temperature ever measured in the country (a reading of 54.4°C/129.9°F observed at the same site on July 16, 2010 has been disallowed as a result of a faulty sensor). The 54.0°C reading also is a new record for Asia and ties a similar reading at Death Valley (on June 30, 2013) as the hottest reliably measured temperature on Earth. The key word here is ‘reliably’. Many hotter temperatures have been reported from around the world in years past. However, all of these have credibility issues. In that vein I am going to revisit a blog I first posted on WU in October 2010 listing all the various claims to temperature readings at or above 54°C (129.2°F). In the years since I made that post I’ve learned more about some of these claims and have thus updated my entries and ‘validity’ scores as a result.

An extraordinary meteorological event; was one of its results a 1000-year flood?

By Stu Ostro
October 5, 2015

The confluence of meteorological ingredients the first weekend in October 2015 resulted in an extraordinary weather event with severe impacts. Was one of them a 1000-year flood?

Why the Arrest of a Science-Loving 14-year-old Matters

By Shaun Tanner
September 16, 2015

By now, many of you have heard or read about the arrest of Ahmed Mohamed, a 14-year-old high school student from Irving, Texas. Ahmed was arrested because school officials called the police after he showed one of his teachers his homemade clock. Mistaken for a bomb, Ahmed was taken into custody, interrogated, shamed, suspended (still on suspension today, Wednesday), and reprimanded. All of this after it has been found that the "device" he brought to school was indeed, a homemade clock.