Wind is the movement of air masses driven by differences in atmospheric pressure, influencing weather patterns and pollutant dispersal. The common sensation that the world is becoming windier is a complex question for atmospheric scientists. To determine if wind patterns are truly changing, researchers analyze decades of precise meteorological data rather than relying on anecdotal experience. The science reveals a nuanced picture that challenges the simple perception of universal windiness, showing that shifts in air circulation are far from uniform across the globe. Investigating these wind trends is paramount for areas like renewable energy and disaster preparedness.
Measuring Wind Trends Over Time
Tracking historical wind speed requires consistent measurement techniques over long periods. The traditional method uses ground-based anemometers, but the reliability of these records is challenged by non-climatic factors. For instance, the growth of trees or new construction near a station increases surface friction and can artificially lower wind readings over time. Scientists must apply homogenization protocols to adjust for these issues, ensuring the data represents climate variation.
Beyond surface measurements, remote sensing technologies provide a broader view of atmospheric circulation. Weather balloons (radiosondes) carry instruments that measure wind speed and direction at various altitudes. Satellites and advanced radar systems, such as LiDAR, track cloud top movement or aerosol particles to create detailed wind profiles at different elevations. These modern tools are valuable for gathering data over oceans and remote areas where ground stations are scarce.
Global Stillness Versus Intensified Local Events
The scientific consensus, based on decades of terrestrial data, points to a phenomenon known as “global stilling.” Between the late 1970s and about 2010, average surface wind speeds over land in many mid-latitude regions decreased by an estimated 5 to 15%. This stilling trend meant that the average day in many places was measurably less windy than in previous decades.
However, around 2010, this decline appeared to reverse in many regions, with speeds picking up again at a faster rate than the previous decrease. This recent increase, combined with the growing intensity of severe weather, contributes to the public perception of a windier world. The observed decline applies mainly to the daily mean wind, which is often less noticeable than a severe storm.
In contrast to the decreasing average speeds, the frequency and intensity of extreme wind events, such as severe thunderstorms and hurricanes, have been increasing. Maximum wind speeds within convective events have been intensifying, meaning that while a typical day may have less wind, the high-impact, damaging days are becoming more severe.
The intensification of tropical cyclones is particularly evident, fueled by rising sea temperatures. This dual trend—lower average wind speed interspersed with more violent, localized windstorms—explains why the memory of a damaging storm often outweighs the experience of calmer days.
Drivers of Changing Atmospheric Circulation
Changes in wind patterns are driven by a combination of local and large-scale atmospheric forces. Global stilling is partly attributed to increased “surface roughness”—growing physical obstacles that frictionally slow down near-surface winds. This roughness is caused by the expansion of urban areas with taller buildings and the increased density of vegetation, such as forest growth, creating more drag on the air.
Changes in large-scale atmospheric circulation also play a significant role. The primary driver of wind is the temperature difference between the warm tropics and the cold poles. The Arctic is warming significantly faster than the rest of the globe (polar amplification), which weakens this temperature gradient.
A weaker temperature gradient tends to slow down the overall global wind system, including the high-altitude jet stream. This slower jet stream can become wavier and more meandering, causing weather systems to move slowly and persist longer. Warmer air also holds more moisture, providing latent heat to fuel severe convective storms, which contributes to the observed increase in maximum wind speeds during these events.
Consequences of Altered Wind Regimes
These shifts in wind patterns have implications for human infrastructure and natural ecosystems. For the wind power industry, the stilling trend poses a significant challenge. Since power output is related to the cube of the wind speed, even a small decrease in average speed leads to a disproportionately large reduction in energy production, requiring new turbine designs efficient at lower speeds.
The increased frequency of intense wind events also affects wind farms, as turbines must shut down automatically at a “cut-out” speed to prevent structural damage. In natural systems, altered wind regimes affect ecological processes like seed dispersal and the movement of airborne pollutants. Stronger gusts can also exacerbate the spread of wildfires, especially when combined with drier conditions.
Wind changes impact agriculture, where weaker winds can reduce pollutant dispersal and intensify heat domes. Conversely, stronger winds increase the risk of soil erosion and dust storms. Over the ocean, wind is the primary driver of currents and upwelling, which brings nutrient-rich deep water to the surface. Alterations to these wind-driven processes can disrupt ocean ecosystems and fisheries.