Record heat waves hit Antarctica and Arctic simultaneously. Here’s what drives them and how they’ll impact wildlife
Record-breaking heat waves hit Antarctica and the Arctic simultaneously this week, with temperatures reaching 47℃ and above-normal 30℃.
Heat waves are weird anytime in Antarctica, but especially now at the Equinox when Antarctica is about to descend into winter darkness. Similarly, to the north, the Arctic is just coming out of winter.
Are these two heat waves linked? We don’t know yet, and it’s most likely a coincidence. But we do know that the Antarctic and Arctic weather systems are connected to the regions closest to them, and those connections sometimes reach into the tropics.
And is climate change the cause? It could be. Although it is too early to say for sure, we know that climate change is making polar heat waves more frequent and more severe, and the poles are warming faster than the global average.
So let’s take a closer look at what is driving the extreme anomalies for each region and the flux effects on polar wildlife like penguins and polar bears.
What happened in Antarctica?
The Antarctic heatwave was caused by a slow-moving and intense high-pressure system located southeast of Australia, which carried large amounts of warm air and moisture deep into the interior of the Antarctic. Antarctic. It was coupled to a very intense low pressure system over the interior of East Antarctica.
To make matters worse, cloud cover over the Antarctic Ice Shelf trapped heat radiating from the surface.
As it is autumn in Antarctica, temperatures inside the continent were not high enough to melt the glaciers and the ice sheet. But that’s not to say that big temperature swings haven’t happened.
For example, Vostok in the middle of the ice shelf reached a tentative high of -17.7℃ (15℃ higher than the previous high of -32.6℃). Concordiathe Italian-French research station also on the high plateau, experienced its highest temperature on record for a month, which was about 40℃ above the March average.
The story is quite different on the coast because the rain fell, which is not really common on the mainland.
The rain was driven mainly by an atmospheric river – a narrow band of moisture collected in warm oceans. Atmospheric rivers are found at the edge of low-pressure systems and can move large amounts of water over vast distances, on scales larger than continental ones.
Despite their rarity, atmospheric rivers make a significant contribution to the continent’s ice sheets, as they dump relatively large amounts of snow. When surface temperatures rise above freezing, rain rather than snow falls on Antarctica.
Last Monday (March 14), air temperatures at Australia’s Casey station peaked at -1.9℃. Two days later, they were more like midsummer temperatures, hitting a new March high of 5.6℃, which will melt the ice.
This is the second heat wave at Casey Station in two years. In February 2020, Casey reached 9.2℃, followed by a shocking peak of 18.3℃ on the Antarctic Peninsula.
Read more: Anatomy of a heat wave: How Antarctica recorded a 20.75°C day last month
So what could this mean for wildlife?
Adélie penguins, which live all along the Antarctic coast, have recently finished their summer breeding. But fortunately, the Adélie penguin chicks had already gone to sea to start hunting for food on their own, so the heat wave did not impact them.
The rain may have affected local plant life, such as mosses, especially since they were in their annual phase of drying out for the winter. But we won’t know if there is any damage to the plants until next summer when we can visit the moss beds again.
What about the Arctic?
A similar weather pattern occurred last week in the Arctic. An intense low pressure system has begun to form off the northeast coast of the United States. An atmospheric river formed at its junction with an adjacent anticyclone.
This weather pattern funneled warm air into the Arctic Circle. Svalbald, Norway recorded a new maximum temperature of 3.9℃.
American researchers have dubbed the low-pressure system a “bomb cyclone” because it formed so quickly, undergoing the deliciously called “bombogenesis.”
Winter sea ice conditions this year were already very low and, on land, there was recent record rainfall across Greenland.
If warm conditions cause sea ice to break up sooner than normal, it could have dire consequences for many animals. For example, sea ice is a crucial habitat for polar bears, allowing them to hunt seals and travel long distances.
Many people live in the Arctic, including indigenous Arctic peoples, and we know loss of sea ice disrupts subsistence hunting and cultural practices.
In addition, the bomb cyclone weather system brought chaotic weather to many populated areas of the northern hemisphere. In northern Norway, for example, flowers started blooming early due to three weeks of abnormally hot weather.
An omen for the future
Modeling suggests that large-scale climate patterns have become more variable. This means that this seemingly unique heat wave may be a harbinger for the future under climate change.
In particular, the Arctic has warmed twice as fast like the rest of the world. This is because melting sea ice reveals more ocean below, and the ocean absorbs more heat because it is darker.
In fact, the Intergovernmental Panel on Climate Change (IPCC) predicts that Arctic sea ice will continue its current decline, with summers without ice possible by the 2050s.
The future of Antarctica seems equally worrying. IPCC finds that global warming between 2℃ and 3℃ this century would see the West Antarctic Ice Sheet almost completely lost. Getting global emissions to net zero as quickly as possible will help avoid the worst impacts of climate change.
Read more: Every Antarctic tourist actually melts 83 tonnes of snow – new research