A September heat wave switching into a snowstorm over one day in the Rocky Mountains. Winter snowfall suddenly melting and saturating fields of dormant crops, before refreezing and encasing them in damaging ice. Early spring warmth prompting plants to blossom followed by a cold snap that freezes and drops their petals.
Rapid temperature change events like these have increased in frequency and intensity over recent decades, a new study found.
The transition periods for these abrupt temperature shifts have also shortened, according to the study, published Tuesday in the journal Nature Communications.
Because the quick changes in temperature give communities and ecosystems little chance to respond, they may pose greater challenges than heat waves or cold snaps alone, said Wei Zhang, an assistant professor of climate science at Utah State University and one of the lead authors of the study.
“The impact could really be cascading on a different level,” he said.
The researchers warned these temperature flips could have damaging effects on people and natural environments, including destruction of crops, harm to ecosystems and strains on power infrastructure. And low-income countries, where there is less access to weather forecasting and infrastructure is less resilient, are more vulnerable.
The researchers examined temperature data from 1961 to 2023 to identify global patterns in sudden weather shifts, where temperatures in an area either jumped from cold temperatures to warm or plunged from warm to cold within five days. They found that instances of these flips increased in more than 60 percent of regions they surveyed.
The largest increases in frequency were observed in South America, West Europe, Africa, and South and Southeast Asia. Some areas, including the polar regions, showed different behavior and experienced fewer events.
While the climate mechanisms driving changes to these temperature-flip events are not yet fully understood, Dr. Zhang said, there is a significant trend showing that these events are becoming more frequent, stronger and quicker in many areas of the globe.
“It’s an intriguing result,” said Philip Mote, a professor at Oregon State University’s College of Earth, Ocean and Atmospheric Sciences, who peer reviewed the study. “They thought to look at the climate system in a different way, as sort of a sequence of weather phenomena.”
Sudden temperature changes can disrupt the growth of plants, posing challenges for agriculture.
Plants are reliant on temperature signals for their development and flips from warm to cold, and vice versa, can confuse their internal systems, said Corey Lesk, a postdoctoral fellow in the Dartmouth College Department of Geography and Neukom Institute who studies the affects of climate change on people and nature. Temperature swings can also complicate farmers’ abilities to plan and prepare fields, including timing fertilizer and pesticide use.
“You’re really fighting against the basic setup of how plants operate, which is they can’t move to avoid stresses,” Dr. Lesk said.
Warming weather signals many plants to begin their spring growing season. Sudden flips between warm and cold, such as “false springs,” can wipe out plants that are just starting to emerge. An example cited in the study of damage from a warm-to-cold flip was in Europe in April 2021: After a period of warm weather, a sudden frost iced many fragile, newly formed plant shoots and buds, leading to widespread crop damage.
Cold-to-warm flips also can be damaging, Dr. Lesk said. Winter wheat, for example, is planted in the fall and survives the winter by being buried under snow. If a temperature flip causes the snow cover to melt suddenly, the plants are at risk of being encased in ice and suffering frost damage before they can continue growing in the spring.
In natural environments, plant loss from these flip events could set off a series of other consequences, like less available food for animals, Dr. Zhang said. Another risk from back-to-back severe temperatures is increased pressure on power systems, which can cause people to lose heat or air-conditioning during dangerous temperatures.
The study referenced a September 2020 event in the Rocky Mountains, when a record heat wave suddenly changed to a heavy, early blanket of snow, with temperatures in some areas dropping more than 50 degrees Fahrenheit in a day. The weather events caused power outages for thousands of people in the region.
Researchers projected that the trend of increasing temperature-flip events would continue to rise as global temperatures climb higher. More research is necessary to determine the underlying dynamics of how these events occur and how they can be better predicted.
Scientists also urged efforts to mitigate potential harms from swings in temperature extremes, such as improving access to cooling centers during heat waves, improving global access to weather forecasts and making power systems more resilient.
“It’s a very new idea,” Dr. Zhang said. “We haven’t had time to really evaluate the impact.”
