January 2025 becomes the hottest January ever recorded worldwide

• Climate change

January 2025 has officially been declared the hottest January ever recorded globally, according to joint reports from the Copernicus Climate Change Service (C3S) and the United States National Oceanic and Atmospheric Administration (NOAA). The global average temperature during this month reached 13.23 °C, exceeding the 1991–2020 reference average by 0.79 °C. Even more alarming, this figure represents an increase of 1.75 °C compared to pre-industrial levels, making it one of the most significant thermal anomalies of the modern era.

This global heat record has surprised the scientific community because it occurred under the influence of La Niña, a climate phenomenon historically associated with lower global temperatures. However, in this case, La Niña’s cooling effect was not enough to counteract the ongoing warming driven by human activities, particularly greenhouse gas emissions.

What is La Niña and why did it fail to cool the planet?

La Niña is a climate phenomenon characterized by anomalous cooling of surface waters in the central and eastern Pacific Ocean. It typically causes a range of climate disruptions worldwide, including a decrease in average global temperatures. However, in January 2025, despite La Niña being active, the planet experienced unprecedented warming.

Experts explain this situation through several interrelated factors:

• Persistence of global warming: Emissions of carbon dioxide (CO₂), methane (CH₄), and other greenhouse gases have continued to rise, pushing global temperatures beyond the temporary cooling capacity that La Niña might normally provide.

• Heat accumulation in the oceans: For years, the oceans have acted as climate buffers, absorbing much of the heat generated by human activity. This accumulated heat is now being gradually released, contributing to rising atmospheric temperatures.

• Reduction of atmospheric aerosols: Aerosols, airborne particles that reflect part of the sun’s radiation back into space, have declined due to changes in global industrial and health policies. This reduction has increased the planet’s ability to absorb solar heat.

Global consequences of the temperature record

The unusual heat recorded in January 2025 was evident across many regions of the world, generating significant climatic, environmental, and social impacts:

• Europe: Numerous regions in southern and eastern Europe experienced unusually high temperatures for the season. Some areas reached historic winter temperature records, affecting energy supply and local ecosystems.

• North America: While cold spells affected parts of Canada and the United States due to polar vortex instability, many other regions experienced above-average temperatures, disrupting seasonal weather patterns.

• Asia and Oceania: In Siberia, abnormally high temperatures accelerated permafrost thaw. In Australia, extreme heat intensified drought conditions and worsened wildfires, impacting both ecosystems and rural communities.

• Africa and South America: Several regions in Africa and South America also experienced significant thermal anomalies, negatively affecting agriculture, water availability, and food security.

Warmer oceans and declining sea ice

Global warming affects not only air temperatures but also ocean temperatures. In January 2025, the average sea surface temperature between latitudes 60°S and 60°N reached 20.78 °C, one of the highest values ever recorded for that month.

This rise in ocean temperature has had devastating effects on polar ice masses. In the Arctic, sea ice extent decreased by 3% compared to the average, while in Antarctica, the loss was even more severe, with a 10% reduction. This places January 2025 among the worst months for sea ice coverage in decades. The disappearance of polar ice has profound implications for climate stability, including ocean current disruption, sea level rise, and the loss of critical habitats.

What does this record mean for the future of the climate?

The January 2025 record is a clear warning sign of the acceleration of climate change. If greenhouse gas emissions continue at current levels, the world is likely to soon exceed the critical 1.5 °C threshold established in the Paris Agreement, potentially triggering a cascade of irreversible climate effects, from ecosystem collapse to more frequent and intense extreme events such as hurricanes, wildfires, and prolonged droughts.

Furthermore, La Niña’s inability to cool the planet as it historically has suggests we may be entering a new phase of the Earth’s climate system, where natural self-regulation mechanisms are losing effectiveness in the face of accumulated human impact.

What can we do to mitigate this crisis?

In light of this scenario, climate action is more urgent than ever. Solutions exist, but they require coordinated and sustained efforts from governments, businesses, and citizens:

• Drastic emission reductions: A strong shift toward renewable energy sources such as solar and wind is essential, along with improving energy efficiency in homes, industries, and transportation, and promoting sustainable mobility models.

• Protection and restoration of ecosystems: Forests, wetlands, and oceans act as natural carbon sinks. Protecting and restoring them is one of the most effective strategies to combat climate change.

• Education and awareness: Informing and educating the public about the causes and consequences of climate change is crucial to driving individual and collective behavioral change.

• Climate adaptation: Beyond mitigation, adaptation is essential. This includes developing resilient infrastructure, effective public policies, and early warning systems to protect the most vulnerable communities from ongoing climate impacts.

Conclusion

The heat record of January 2025 is not an isolated event but part of a sustained global trend reflecting the rapid transformation of Earth’s climate. We are experiencing the consequences of decades of inaction and dependence on fossil fuels. While there is still time to avoid the worst outcomes, the window of opportunity is closing rapidly. The time to act is now.