How do freezing temperatures persist even though the world is warming? (© Masque - stock.adobe.com)
In a nutshell
- Record-breaking cold hit eastern China in December 2023 during Earth’s warmest year, with Beijing experiencing its longest freezing spell since 1951. Scientists found that unusual atmospheric patterns, linked to Arctic warming, caused 83% of the cold event’s intensity.
- Climate change actually made this cold snap less severe than it would have been in pre-industrial times, reducing its intensity by up to 22%. The frequency of such extreme cold events has already dropped by 92% due to global warming.
- By 2100, similar cold events could become up to 95% less frequent and 2°C less intense under moderate emission scenarios. However, if the world achieves the Paris Agreement’s 1.5°C target, cold snaps might remain similar to current levels, suggesting the need for continued winter preparedness.
BEIJING — Just because Earth is warming to extreme highs doesn’t mean freezing temperatures will disappear. In 2023, Earth experienced its hottest year in recorded history, yet parts of the Northern Hemisphere shivered through bone-chilling cold snaps that broke decades-old records. The most dramatic of these weather extremes struck eastern China in December, sparking new international research that helps explain how record cold can exist in an increasingly warm world.
For atmospheric scientists, this weather paradox demanded an explanation. In the study, published in npj Climate and Atmospheric Science, researchers have unraveled how such intense cold can occur in an increasingly warm world. Their findings not only explain 2023’s extreme events but also offer insights into what similar weather patterns might look like in our warming future.
The December 2023 cold wave rewrote the record books across eastern China. Beijing endured 300 straight hours of temperatures below freezing, the longest such stretch since temperature tracking began in 1951. Throughout the region, 78 weather stations logged their lowest December temperatures ever recorded, while 12 locations broke their all-time low-temperature records. At its most extreme, some areas saw temperatures plummet nearly 12°C (about 22°F) below normal winter conditions.
The Chinese cold snap wasn’t an isolated incident. Similar extreme cold events struck Northern Europe in early January 2024 and much of the United States in mid-January 2024. These widespread cold events during Earth’s warmest years on record sparked intense scientific interest and public debate about the relationship between global warming and extreme winter weather.
A key to understanding these events lies in an atmospheric pattern scientists call “Warm Arctic-Cold Eurasia.” During the Chinese cold snap, the Arctic region experienced unusually warm temperatures, the fourth warmest on record for that time of year. This warmth disrupted the normal temperature gradient between the Arctic and mid-latitudes, weakening the atmospheric patterns that typically keep cold polar air contained near the North Pole. The disruption allowed frigid Arctic air to flow southward into regions like China.
In the middle of the atmosphere, an unusually strong high-pressure system positioned itself over Lake Baikal in Eastern Siberia, ranking as the third strongest such system recorded for December in that region since 1959. This blocking pattern, combined with a record-breaking high-pressure system over Siberia, created the perfect conditions for channeling Arctic air southward into China.
“Our findings confirm that human-induced climate change is actually weakening extreme cold events,” explains lead study author professor Cheng Qian from the Institute of Atmospheric Physics, in a statement. “The record-breaking cold in December 2023 was primarily caused by unusual large-scale atmospheric circulation patterns, which accounted for 83% of its intensity. Meanwhile, the warming effect of climate change reduced the event’s severity by up to 22%.”
The research team, which included collaborators from the University at Albany and the Chinese Academy of Meteorological Sciences, used climate model simulations to analyze how human activities have already affected such cold events. Their analysis revealed that due to anthropogenic warming, the likelihood and intensity of cold events like the 2023 episode have already dropped by over 92% and 1.9°C respectively, compared to a world without human influence.
Looking toward the future, the study projects that such extreme cold events will become increasingly rare by the century’s end under moderate emission scenarios. The likelihood of similar cold snaps could decrease by about 95%, while their intensity might diminish by about 2°C (about 35°F) compared to today’s events. However, this projection comes with an important caveat.
“If carbon neutrality is achieved and global warming stabilizes at 1.5°C, we could see cold extremes similar to those we experience today,” says Qian. “That means societies still need to be prepared for sudden cold snaps, even when the 1.5°C target of the Paris Agreement is achieved.”
As communities worldwide grapple with climate change, this research provides crucial insights into the future of winter extremes. While global warming generally means milder winters, the potential for severe cold events remains—requiring continued vigilance in winter preparedness even as the world works to reduce emissions.
Paper Summary
Methodology
The researchers used three main approaches to analyze the December 2023 cold event. First, they examined weather records dating back to 1959 to understand how unusual this cold snap was. Second, they used climate models to simulate conditions both with and without human-caused climate change. Third, they employed statistical techniques to separate the influence of natural weather patterns from human-influenced climate factors. The team focused particularly on daily maximum temperatures across eastern China and analyzed atmospheric circulation patterns that drive extreme cold events. They used multiple climate models to ensure their findings were robust and not dependent on any single model’s quirks.
Results
The study found two major drivers behind the 2023 cold event. The primary factor was an unusual atmospheric circulation pattern linked to Arctic warming, which accounted for 83% of the cold snap’s intensity. However, climate change actually reduced the event’s severity by 6-22% compared to what it might have been in pre-industrial times. Looking forward, similar cold events will become much rarer by 2100, with their frequency decreasing by up to 95% under moderate emission scenarios. If the world achieves the Paris Agreement’s 1.5°C target, such cold events might remain similar to today’s levels.
Limitations
Several factors limit the study’s conclusions. The relatively short period of reliable weather records (since 1959) makes it challenging to fully understand rare extreme events. The climate models used, while sophisticated, can’t capture all the complexities of atmospheric processes. Additionally, since the study focused specifically on eastern China, its findings might not apply to other regions experiencing extreme cold events. The researchers also note uncertainty in future projections, particularly regarding how atmospheric circulation patterns might change in a warming world.
Discussion and Takeaways
This research helps explain how extreme cold events can occur even as the planet warms. While global warming makes cold snaps less frequent and less severe overall, unusual atmospheric patterns can still produce record-breaking cold temperatures. The study suggests that communities need to maintain winter preparedness even as they adapt to a warming climate. The findings also highlight how global warming affects different aspects of weather systems – while it generally makes winters milder, it can also disrupt atmospheric circulation patterns in ways that occasionally allow Arctic air to push southward.
Funding and Disclosures
The research was supported by multiple organizations: the National Natural Science Foundation of China (grant no. 42341203), the Chinese Academy of Sciences Project for Young Scientists in Basic Research (grant no. YSBR-086), and the Jiangsu Collaborative Innovation Center for Climate Change. The researchers acknowledged technical support from the Earth System Numerical Simulation Facility. All authors declared no competing interests that could have influenced their findings.
Publication Information
The study “Attribution of a record-breaking cold event in the historically warmest year of 2023 and assessing future risks” was published in npj Climate and Atmospheric Science (2025) volume 8, article number 14. The work represents a collaboration between the Institute of Atmospheric Physics at the Chinese Academy of Sciences, the University of Chinese Academy of Science, the University at Albany, State University of New York, and the Chinese Academy of Meteorological Sciences.
