Study finds sharp rise in extreme day-to-day temperature swings worldwide

ISTANBUL

Extreme day-to-day temperature swings have intensified markedly in recent decades, particularly in low- and mid-latitude regions where most of the world’s population lives, according to a study published in the journal Nature.

The research, conducted by scientists from Nanjing University and the Chinese Academy of Sciences, analyzed climate data from 1961 to 2020 and projections extending to 2100. It found that sudden, large temperature fluctuations from one day to the next -- a largely overlooked form of extreme weather -- are becoming more frequent, more intense and larger in magnitude.

The study attributes the trend primarily to greenhouse gas emissions, with drier soils and increased variability in air pressure and soil moisture identified as key contributing factors. While high-latitude regions have experienced fewer of these swings, low- and mid-latitude areas in both hemispheres show a clear and accelerating increase.

Researchers warned that climate change is making daily weather far more volatile in warmer regions and that this volatility is expected to worsen through the end of the century.

The strongest increases were recorded in the western United States, eastern China, parts of South America and the Mediterranean basin. Over 10-year periods, intensity rises reached 11.1 degrees Celsius (20 degrees Fahrenheit) in the western US, 9.4C in eastern China, 12.4C in South America and 7.1C in the Mediterranean.

Record-breaking daily temperature swings were observed in 2022, with eastern China experiencing a 22.9C shift and the western US recording 20.3C. The study found that such record-level events are now occurring far more often than under historical climate conditions.

- Greenhouse forcing the main driver

Deniz Demirhan, a climate scientist at Istanbul Technical University, told Anadolu that global warming is amplifying day-to-day temperature variability in mid-latitudes while reducing it in polar regions.

“Climate change alters cloud patterns and atmospheric moisture, which directly affects daily temperature cycles,” Demirhan said. In some cases, increased cloud cover limits daytime heating and nighttime cooling, narrowing temperature ranges, while in others, warming sharpens contrasts between day and night.

She stressed that greenhouse gas forcing is the main long-term driver of changes in daily temperature variability, as rising concentrations disrupt Earth’s energy balance, warm the planet and alter atmospheric circulation and surface processes.

In low and mid-latitudes, Demirhan said, this leads to more variable pressure systems, drier soils, persistent high-pressure patterns and frequent droughts -- conditions that allow sharp heat spikes followed by sudden temperature drops. By contrast, rapid warming in the Arctic reduces the temperature gradient between the equator and the poles, resulting in fewer severe cold outbreaks and more moderate daily fluctuations at high latitudes.

- Impacts on health, economy and agriculture

Demirhan warned that abrupt temperature swings can weaken immune systems, trigger health problems and increase mortality by stressing cardiovascular and respiratory systems, potentially leading to more strokes, heart attacks and asthma attacks.

Economically, she said, such volatility can cause agricultural losses, sudden spikes in energy demand, strain infrastructure and disrupt broader economic activity.

Climate model projections for the 2050-2100 period show a significant rise in both the frequency and severity of extreme day-to-day temperature swings across low, subtropical and mid-latitude land regions. Under high-emissions scenarios, the frequency of these events could increase by 17%, their average magnitude by 3% and the annual accumulated heat load by 20%.

Those projections are drawn from assessments by the Intergovernmental Panel on Climate Change, the United Nations’ leading authority on climate science.

The findings suggest that sudden, hard-to-predict temperature fluctuations could become a defining feature of daily weather in many densely populated regions, posing growing challenges for public health systems, economies and food security worldwide.