Despite its verdant-sounding name, Greenland is anything but green. In fact, the land of ice and snow is home to the world’s second-largest ice sheet and it once recorded a blustery extreme negative temperature of -69.6ºC (-93.3ºF).
However, our rapidly changing climate has brought some not-so-chilly weather phenomena to the world’s largest island: rain.
Yep, that’s right—it rained in Greenland.
Okay, rain in Greenland isn’t actually uncommon and it does happen at some of the lower-lying coastal locations in the southern part of the island. However, on August 14, 2021, a weather station at the highest point on the Greenland Ice Sheet recorded rain and above-freezing temperatures for about 9 hours in row.
According to the National Snow and Ice Data Center (NSIDC), rain has never been recorded at this weather station, which is located some 10,551 feet (3,216 m) above sea level. While the weather station has had above-freezing temperatures 3 times in the last decade, liquid precipitation is a brand new occurrence.
Climate Change & Weather Anomalies
Now, while a bit of rain at a remote weather station doesn’t exactly qualify as “extreme weather,” the fact that it rained at the highest elevation locale in Greenland should capture your attention.
Of course, the reasons behind this rain event aren’t exactly a mystery. While no one can pin a single weather event solely on climate change, we can see a very clear trend in warming temperatures in Greenland that have led to this funky weather anomaly.
According to researchers at the Danish Meteorological Institute, ice cores from the Summit weather station (where the rain was recorded) show that above-freezing conditions at that location have only been recorded 6 times in the last 2,000 years. When we consider that 3 of these 6 occurrences occurred in the last 10 years, then it’s clear that something odd is happening with our climate (newsflash: climate change).
Overall Weather Patterns
The link between anthropogenic climate change and warming conditions in the Arctic is nearly indisputable at this point. So, what’s most interesting here is the weather patterns that were at play to give us this rain event in Greenland in the first place.
First and foremost, the Greenland Ice Sheet actually experienced two major melt events during July 2021. While the overall atmospheric conditions in this region are complex, there are a few key metrics we can focus in on to better understand this melt event and the rain that followed in August.
If we first take a look at the temperature anomalies (i.e., the difference in surface temperatures from a long-term average) in Greenland during the boreal summer of 2021, it’s clear that the bulk of the island is experiencing warmer than average temperatures (see figure above) at the surface.
Additionally, by looking at the 700 mb height anomalies for this same time period, we see that there was a strong negative height anomaly over Greenland for much of the summer. We can use 700 mb heights as a sort of anomaly for mid-level air pressures.
As such, we can see that a negative height anomaly indicates that there was a much lower average pressure over Greenland and much of the Canadian Arctic during the boreal summer of 2021. This is important to note because this low pressure system likely pulled warm air up from the southern part of Greenland toward the northern part of the island.
In fact, if we take a look at the average sea level pressure over Greenland on the day of our rain event (see above image), we find that there was, indeed, a decently strong low pressure system that formed over the Hudson Bay while there was a high pressure system off the southern coast of Greenland. This helped to create a strong pressure gradient that helped drive warm, moist air onto Greenland and toward the Summit weather station.
Rain, Rain Go Away
The rain event of Augst 14, 2021 at the Summit weather station in Greenland is certainly a weather anomaly.
Of course, attributing a single weather event to climate change is tricky to do, but the data strongly suggests that Greenland is getting warmer. As such, these rainy days at the top of the world’s second-largest ice sheet might become a more regular occurrence in the future as the Arctic warms faster than nearly any other region on Earth.