How global warming can trigger extreme cold

Scientists have increasingly examined how global warming can still be linked to severe cold outbreaks. At first, this sounds contradictory: if the planet is warming, why do extreme freezes still happen? The answer lies in the difference between climate and weather, and in the way a warmer atmosphere can disrupt large-scale air and ocean circulation.

What is the trend?

The global climate continues to warm. 2024 remains the warmest year ever recorded, while 2025 was still one of the three warmest years on record, around 1.43°C above the 1850–1900 average, according to the World Meteorological Organization. The period from 2015 to 2025 was the warmest 11-year period on record.

Europe is warming fast as well. Copernicus reported that 2025 was the third-warmest year on record both globally and for Europe, with 2024 still holding the global record.

At the same time, cold waves still occur — sometimes intensely. This does not disprove global warming. Climate change describes the long-term shift in average conditions, while weather describes short-term fluctuations over days or weeks. A warming climate does not remove winter; it changes the background conditions in which winter weather develops.

Extreme cold does not contradict global warming

Global warming is the long-term rise in global average temperature since the industrial era, mainly driven by increasing concentrations of greenhouse gases such as carbon dioxide and methane.

It is also connected to a broader rise in weather extremes: heatwaves, wildfires, heavy precipitation, droughts, floods, storms, and, in some cases, disruptive cold spells. The key point is that climate change does not simply make every place warmer every day. It can destabilise familiar atmospheric patterns.

For Europe, this matters especially in the northern and temperate latitudes – from Scandinavia and the North Sea region to Central and Eastern Europe – where winter weather depends strongly on the behaviour of the jet stream, Arctic air masses, and the polar vortex.

Why extreme cold can still happen

The link between global warming and extreme cold is more complex and less settled than the link between global warming and heatwaves. But several mechanisms are increasingly discussed by scientists.

One of them is Arctic amplification. The Arctic is warming faster than the global average. As the temperature difference between the Arctic and the mid-latitudes weakens, the usual west-to-east flow of air can become more wavy. These waves can allow warm air to move unusually far north – and cold Arctic air to spill unusually far south. The Arctic Council has described how a more wavy polar jet stream can contribute not only to cold spells, but also to persistent heatwaves, floods, storms, and droughts.

The polar vortex effect

Another important factor is the polar vortex – a large band of strong winds that forms high above the Arctic in winter. Under stable conditions, it helps keep very cold air trapped near the pole. But when the vortex weakens, stretches, or splits, cold Arctic air can move southward into North America, Europe, or Asia.

This mechanism was visible again at the start of 2026. The WMO noted that a weakened and distorted polar vortex helped drive intrusions of frigid air into the mid-latitudes, contributing to cold snaps in North America, Europe, and Asia.

In Europe, this means that a warmer Arctic can sometimes create highly unstable winter patterns: one week may feel unusually mild, while the next can bring a sharp freeze, heavy snow, or icy winds.

The role of the Atlantic Ocean

Ocean circulation may also affect winter extremes. The Atlantic Meridional Overturning Circulation, or AMOC, moves warm water northward through the Atlantic and helps keep much of Europe milder than it would otherwise be at similar latitudes.

Scientists expect the AMOC to weaken as the climate warms, because warming seas, melting ice, and increased freshwater input can disturb the density-driven circulation of the North Atlantic. Carbon Brief describes the AMOC as a system that helps keep Europe warm and regulates rainfall patterns, while also noting that it is under threat from human-caused climate change.

A weaker AMOC would not mean that Europe suddenly stops warming overall. But it could reshape regional patterns, increasing the risk of sharper contrasts: warmer averages, stronger heat extremes, and potentially more disruptive cold events in some European regions.

What scientists expect next

The overall direction is clear: winters are expected to become warmer on average. Extremely hot days are becoming more common, while record cold events are becoming less frequent globally. Recent research summarised by Carbon Brief found that record cold events have become roughly twice as rare, while heat records have increased strongly under climate change.

But "less frequent" does not mean "impossible." Europe can still experience severe cold spells, especially when atmospheric circulation patterns align in the right way. A warming climate raises the baseline temperature, but it also loads the atmosphere with more energy and moisture, making weather swings more disruptive.

The practical takeaway is simple: global warming does not eliminate winter. It makes the climate system less stable, increasing the probability of extremes – from record heat and floods to sudden winter cold outbreaks. For Europe, the challenge is therefore not only preparing for hotter summers, but also building resilience to more volatile seasons overall.

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