sudden stratospheric warming

Sudden stratospheric warming (SSW) is a meteorological event where the temperature in the stratosphere, a layer of Earth's atmosphere, rapidly increases. This phenomenon typically occurs during winter in the polar regions. The stratosphere extends from about 10-18 km to 50 km above Earth's surface.12

SSWs can weaken the polar vortex, a large area of low pressure and extremely cold air above the poles. When the polar vortex weakens or becomes unstable, it can expand southward, bringing frigid Arctic air into mid-latitude regions like North America and Eurasia. These cold air outbreaks can cause significant drops in temperature, leading to crop losses, harm to livestock, and even fatalities. While SSWs generally cause global cooling due to stratospheric aerosol absorption, changes in winter wind patterns can sometimes lead to warmer winters in specific areas like Europe.324