Science

Warming Weakens the Polar Vortex

Arctic warming weakens the polar vortex, slows the jet stream, and creates more extreme weather. Natural fluctuations will always exist, but global warming is affecting the entire planet.

T Jackson

21 Jan 2026 — 4 min read

Photo by Annie Nyle on Unsplash

Abstract

Arctic warming weakens the polar vortex, slows the jet stream, and creates more extreme weather. Natural fluctuations will always exist, but global warming is affecting the entire planet.

Global warming is altering the planet’s climate systems, affecting both the polar vortex and the jet stream. Some critics say these changes are only natural, but physics shows that warming, especially in the Arctic, is a key factor. To understand this, it’s important to see what critics get right and what the science explains.

How global warming impacts the polar vortex

The Arctic air drives the polar vortex by being colder than most of the planet, making it more extreme in winter. Cold air leads to low pressure, and Earth’s rotation makes winds spin around the pole, creating a circular flow. This usually envelops the cold Arctic air. The winds are strongest in the stratosphere, far above the weather at the surface.

Global warming does not, and will not, cause the Earth to experience uniform heating. The Arctic is warming much faster than other areas. Scientists call this Arctic amplification. When ice and snow melt, they expose darker ocean and land. Of course, this absorbs more sunlight, increasing warming. This shrinks the necessary temperature gap between the Arctic and lower latitudes.

This is important because the temperature difference is the engine of the polar vortex. When this difference shrinks, the vortex becomes less stable. A weaker vortex is more susceptible to disturbances from atmospheric changes in warmer areas. These disturbances can cause quick spikes in stratospheric warming. In these events, polar stratospheric temperatures rise significantly in a few days. Afterward, the vortex can stretch, move, or split, letting cold Arctic air flow south into North America, Europe, or Asia. This is visible in the jet stream.

It’s important to note that global warming does not create cold air. Instead, it weakens the systems that usually hold cold air closer to the Arctic.

How global warming affects the jet stream

The jet stream is closely linked to the polar vortex. The same temperature difference between cold air near the pole and warmer air farther south powers it. When this difference is large, the jet stream moves quickly and follows a predominantly straight west-to-east path.

As Arctic amplification weakens the temperature difference, the jet stream slows down. Slower jet streams form bigger north-south waves, called Rossby waves. These waves let cold air reach farther south and warm air move farther north. Stagnant waves create long-lasting weather patterns. These can include cold spells, heat waves, droughts, and extended storms. The cold wave in Texas in February 2021 connects to the long heatwave in Europe in 2022. Both events involve strong, persistent Rossby waves that affect the jet stream (see Time, 2023; Nature, 2022). Four key points link the weakening jet to extreme weather: Rossby waves are real and shape large-scale weather.

Arctic amplification is real and reduces the pole-to-equator temperature difference. Slower average wind speeds in some regions are consistent with weaker temperature gradients.

Persistent weather patterns, "blocking events," have increased in some regions and seasons.

This explains why we can still have extreme winter cold even as the world warms. The average temperature goes up, but the weather becomes more extreme.

What critics argue

Global warming doubters often use three main scientific arguments to dismiss its impact on the jet stream.

First, they focus on natural variability. The jet stream often shifts north and south. This happens because of natural cycles like El Niño, volcanic eruptions, and random atmospheric changes. Yet critics refuse to accept the evidence that these patterns are now occurring more often and lasting longer than before.

Second, critics say that warming should make cold extremes less common, not more. They say that rising global temperatures make it hard to explain cold outbreaks using climate science. This mixes up averages with variability. A warmer climate does not cut cold air; it changes how cold air moves and how often it leaves the Arctic.

Third thing, critics say that because climate models don’t always agree, the science must be weak. All models agree: a smaller temperature difference between the poles and the equator means slower, wavier jet streams. Researchers base this finding on basic atmospheric physics, not model predictions.

The correct science

To understand how global warming affects the weather, we need a clear story. This story combines observations, theories, and models. Observational data show that the Arctic is warming almost four times faster than the global average. This rapid warming reduces the temperature gradient between the Arctic and the equator. Physics shows that this weaker gradient reduces wind strength. As a result, atmospheric waves become stronger. Satellite and weather observations support this effect. They show that jet streams are more variable now. Also, persistent weather patterns are lasting longer. Models show that a smaller temperature difference causes slower, wavier jet streams. Yet, it is important to note that these models have limitations. They handle uncertainties associated with initial conditions. This affects how complex atmospheric processes unfold. Rossby wave theory explains how slower winds cause bigger swings north and south. Also, data from the stratosphere show that disruptions to the polar vortex happen more often now. These elements create a strong chain of cause and effect. Each link supports the next, providing a clear explanation of the ongoing climate changes.

The bottom line

Critics assert that we must consider natural variability, but this aspect does not encompass the entire story. Global warming does not replace natural processes; it is changing them. By weakening the polar vortex and slowing the jet stream, Arctic warming is increasing the frequency of extreme weather. The planet is getting warmer, and, in turn, the atmosphere is less stable.