Unexpected Heat Pushes Global Temperatures Further Above Preindustrial Levels, Raising Concerns Over Future Climate Trends

Climate scientists are grappling with the unexpected persistence of record-high temperatures as January 2025 marked the hottest on record. Despite the expected cooling effects from a La Niña weather phase, the global temperature anomaly surged to 1.75°C above preindustrial levels, continuing the trend of unprecedented warmth observed over the past few years.

According to the Copernicus Climate Change Service, the EU-funded Earth observation programme, this ongoing heat has baffled experts, who anticipated a dip in temperatures after the El Niño event of 2024 gave way to La Niña. Instead, the global heat has remained near-record levels, suggesting that other factors may be driving the warming.

Samantha Burgess, strategic lead for climate at the European Centre for Medium-Range Weather Forecasts, remarked on the surprise of these continued high temperatures, emphasising the need for monitoring ocean temperatures and their role in climate evolution throughout 2025. The Copernicus report also noted extreme weather variations, with eastern Australia experiencing wetter-than-average conditions while other regions saw drier-than-usual weather patterns.

The January 2025 data marked the 18th of the past 19 months to see surface temperatures surpass the 1.5°C threshold compared to preindustrial times. This signals a critical moment in the fight against climate change, as per the Paris Agreement, where global leaders pledged to limit warming to 1.5°C. While this threshold remains based on long-term warming trends rather than short-term monthly data, the continuing exceedance of this level raises serious concerns.

Julien Nicolas, a climate scientist at Copernicus, described the ongoing heat as unexpected, particularly given the anticipation of cooling influences from La Niña. Despite this, the warming has persisted, and experts are now focused on understanding why the typical cooling pattern hasn’t materialised. The lack of cooling is compounded by unusually warm sea-surface temperatures in various oceans and seas, including a record-low Arctic sea ice extent.

While Copernicus predicts 2025 will likely be the third-hottest year on record, the underlying causes of this warming remain unclear. Natural phenomena like El Niño have been seen as key drivers, but they alone cannot explain the current trends.

One emerging theory points to the shift to cleaner shipping fuels in 2020, which has reduced sulphur emissions that historically helped reflect sunlight, thereby accelerating the warming process. Another theory revolves around changes in cloud cover, particularly low-lying clouds, which may allow more heat to reach the Earth’s surface. This remains a topic of debate among scientists.

The Copernicus Climate Change Service utilises vast data from satellites, ships, and weather stations, extending its records to the 1940s. This wealth of data, alongside historical sources like ice cores, tree rings, and coral, suggests that the current warmth is likely unprecedented in at least 125,000 years. As the temperature anomalies persist, scientists continue to search for answers and monitor the evolving climate, with ocean temperatures expected to provide crucial insights into the planet’s future trajectory.