A rare phenomenon—sudden stratospheric warming over Antarctica—could lead to abnormally hot and dry conditions in parts of southern Australia. This unusual event, which has occurred only a few times in the last 45 years, may disrupt weather patterns and could have significant impacts on the coming summer.
What is Sudden Stratospheric Warming?
At its core, sudden stratospheric warming (SSW) refers to a rapid increase in temperature in the stratosphere, the layer of the atmosphere about 30 kilometers above the Earth’s surface. This is exactly what’s happening over Antarctica right now.
Air temperatures that are typically around minus 50°C are now hovering at about minus 20°C, which is a massive 30°C increase. And it’s not just the temperatures that have changed—the polar vortex, which usually whips around at speeds of around 200 km/h, has slowed down considerably, now sitting closer to 100 km/h.
So, why does this matter? Well, when the stratosphere warms up like this, it can disrupt the usual weather patterns. In the past, similar events have led to hotter, drier conditions in southeastern Australia, particularly in the spring months.
The last time something like this happened was in 2019, and that year saw the intensification of the devastating Black Summer bushfires, reminds The Guardian. So, it’s easy to see why this year’s stratospheric warming is raising concerns.
A Tug of War Between Wet and Dry
The effects of this warming on local weather are still unclear, and meteorologists are keeping a close eye on the situation. Dr. Martin Jucker, a senior lecturer in atmospheric science at the University of New South Wales, explained that there’s a balancing act going on between two competing weather drivers.
On one hand, there are unusually warm ocean temperatures, which typically bring wetter conditions. On the other hand, the stratospheric warming could push the weather towards drier conditions, making it harder to predict which force will win out.
The Bureau of Meteorology has already forecasted wetter-than-usual conditions, but the sudden warming could throw a wrench into that prediction. In the past, stratospheric warming events have caused springtime temperatures to rise and rainfall to decrease, particularly in New South Wales and southern Queensland.
What’s at Stake?
This kind of rare event is more common in the northern hemisphere, where sudden stratospheric warming occurs about six times a decade. But in Australia, it’s something of a rarity, with only three major events in the past 45 years—1988, 2002, and 2019. So, while the current warming is substantial, it’s not as intense as it was in 2019 or 2002. Still, it could have significant implications for this summer’s weather, especially when it comes to hot, dry days in the southeast.
Despite the potential negative impacts, there’s a silver lining: when the stratosphere warms above a certain threshold, it can help reduce the size of the ozone hole, which has been a major environmental concern for decades. So, not all the news is bleak.
The Unpredictability of Weather
As always with weather, there’s a lot of uncertainty. While past events have shown that sudden stratospheric warming can lead to warmer, drier conditions, the meteorological community isn’t entirely sure what will happen this time around.
It’s clear that southeastern Australia could experience hotter-than-usual days, but whether they will be coupled with drought-like conditions or unexpected rainfall remains to be seen. As meteorologists continue to track these changes, we can only wait and see what effects this rare event will have on our summer weather.
