Hottest January on Record Globally but it was Cold in USA

Climate Change - January 2025 Anomalies and Emerging Explanations

January 2025 presented a paradox: while the contiguous United States experienced its coldest January in 37 years, the planet as a whole recorded its warmest January on record, continuing a trend of extreme heat observed over the past two years. This anomaly has intensified concerns among scientists, leading to investigations into potential contributing factors beyond El Niño and decreased aerosol pollution. Emerging research suggests that declining cloud cover, potentially driven by a feedback loop linked to warming temperatures, may be playing a significant role in the accelerating rate of global warming. The implications of these findings, coupled with concerns about the climate's sensitivity to carbon loading and the potential for exceeding established warming targets, are prompting consideration of controversial solutions like Solar Radiation Modification (SRM).

Main Themes & Key Ideas:

1. Contrasting Regional and Global Temperatures:

• The contiguous U.S. experienced a notably cold January 2025. According to NOAA, it was "the Lower 48's chilliest January since 1988... 0.89 degrees Fahrenheit colder than the 20th century January average." Some cities in the Southeast experienced their top 10 coldest Januaries.
• Despite this regional cold, globally, January 2025 was the warmest on record, surpassing the previous record set just one year prior. According to the European Copernicus Climate Change Service (C3S), January 2025 was the planet's warmest January.
• This occurred despite a weak La Niña, which typically has a cooling effect on global temperatures. "Perhaps what was so stunning about this was it happened during a weak La Niña."

1. Acceleration of Global Warming and Scientific Concern:

• The record-setting temperatures represent a continuation of a trend observed since June 2023, leading scientists to express concern and even alarm. "The world set another monthly heat record in January. That may sound like something we’ve heard a lot lately, but this latest record has scientists mysti ed, surprised and even 'terri ed.'"
• The consistency of record heat is described as "anomalous even by the standards of the last two years." Some scientists use adjectives like "surprising," "unexpected" or "anomalous."
• James Hansen's research indicates an underestimated pace of global warming, accelerating by more than 50% in the last few years. The team expects that 1.5°C is now pretty much the climate’s baseline.

1. Cloud Cover and Planetary Albedo:

• Two new studies suggest that declining cloud cover contributes to the acceleration of global warming. The Washington Post reports: "Two new studies offer a potential explanation: fewer clouds. And the decline in cloud cover, researchers say, could signal the start of a feedback loop that leads to more warming."
• Reduced low-altitude cloud cover has decreased the Earth's reflectivity (albedo). "They found that low-altitude cloud cover has fallen dramatically — which has also reduced the reflectivity of the planet. The year 2023 — which was 1.48 degrees Celsius above the preindustrial average — had the lowest albedo since 1940."
• One study estimates that decreased albedo contributed 0.2 degrees Celsius of warming to 2023's record temperatures. "That low albedo, Goessling and his co-authors calculated, contributed 0.2 degrees Celsius of warming to 2023’s record-high temperatures."