Where Exactly Is The Arctic?
Birch leaves float in a small pool in the boreal forest of Tromso.
The plane coming into Tromso skirted close to the tops of the mountain as we dropped into the fjord for landing. The landscape out the window felt familiar. This close to the mountains, I was nearly convinced I was in a small prop plane in Alaska. Only when I turned back to the interior of the plane was I reminded that I was on a large commercial flight in Norway.
Fireweed grows in this part of the world, too! I found it growing on the edge of the sidewalk in Tromso.
I hopped in a taxi from the airport. On the side of the road, I saw familiar plants like fireweed and sour dock. Then, another plant caught me attention. I kept whipping my head around, trying to get a better look as we drove past. It looked like pushki (cow parsnip, Heracleum maximum), but just a little bit different. The more I saw it, the more intrigued I became. A visit to the Tromso Arctic-Alpine Botanic Garden confirmed that it was indeed a close relative of pushki. Called Tromsopalme here and hogweed elsewhere, Heracleum persicum is actually an invasive species and was in 'The Unwanteds' section of the botanical garden.
This plant, called Tromsopalme here, is a relative of the pushki that grows back home.
Head swirling from lack of sleep and jet lag, after checking into my hotel I went to find some dinner. Suddenly, I was awash in the smell of cottonwood, with a hint of low tide. Yes, even those beloved scents lived here in downtown Tromso. Hiking a ways up a mountain in the early morning, I found familiar alpine/tundra plants like low-bush blueberry, crowberry, and cotton grass. Magpies chased each other through the air. I contemplated how I had flown halfway around the world from Homer to Tromso. Yet the plant and animal life was so similar!
In some ways, this made sense. Though I had flown thousands of miles, I had stayed at relatively the same latitude. It made sense that the boreal forest around Tromso's lower elevations felt familiar, as did the alpine/tundra that could be found up on the hills and mountains surrounding Tromso. And yet, re-examining the map, I realized that Tromso was actually about 10 degrees of latitude farther north than Homer. It turns out that Gulf Stream flows across the North Atlantic, bringing warm water. That heat energy dissipates into the atmosphere in northern Eurpoe, making Norway about 10-15 degrees celsius warmer then it might otherwise be. There is concern that a changing climate may disrupt this system, but many questions remain. The Bjerknes Centre for Climate Research provides a good overview.
For me, all this brought up the question a Homer Middle School student asked with some chagrin before I left: "Where exactly is the Arctic?" At first glance this question seems simple, but delineating the Arctic is actually a complex and even controversial task. I'll try to walk you through it here, and have thrown in some photos of the beautiful alpine autumn I enjoyed this morning.
There are three ways the Arctic is typically defined.
Many choose to think of the Arctic as the land of the 'midnight sun' and 'polar night.' Scientifically, these poetic descriptions refer to the region that receives more than 24 hours of daylight on the summer solstice and more than 24 hours of darkness on the winter solstice. This definition of the Arctic draws a nice, clean line around the globe at the Arctic Circle, Latitude 66 degrees and 34 minutes North.
A view across the alpine landscape before sunrise, with the moon peaking through the clouds.
Others define the Arctic as the area North of the Arctic tree line. This line is much more wavy and wobbly, following the boundary between boreal forest and shrubby tundra.
Grasses, lichens, berries, and birches in lovely autumn colors.
Additionally, the Arctic is often delineated by temperature, specifically the 10 degrees celsius isotherm. For this definition, the Arctic includes anywhere in high latitudes where the average daily summer temperature does not exceed 10 degrees celsius (50 degrees fahrenheit). The isotherm draws the most convoluted line, including large parts of the Aleutian Peninsula in Alaska that are more than 10 degrees south of the Arctic Tree Line and Arctic Circle.
Looking out across the alpine plants at sunrise.
And all of these boundaries are moving! In many places, changing climate is driving the 10 degrees celsius isotherm farther north. According to the 2018 Annual Report of the Alaska Climate Research Center many places in the state long considered 'Arctic' had average July temperatures well above 10 degrees celsius. Bethel had average temperatures over 13 degrees celsius in July 2018 and Nome saw averages of over 11 degrees celsius that month. 2019 was even warmer.
Tree line is also shifting due to climate change, though the impacts differ across regions. In some places, the Arctic tree line is expanding northward due to thawing permafrost and warmer air and soil temperatures. But in other areas, insects, wildfire, or drought are impacting trees and limiting their expansion north or even pushing the tree line south.
And even the seemingly straightfoward line of the solstice-based Arctic Circle is fickle! As the tilt (obliquity) of the earth changes over time, so does the location of the line delineating places that experience midnight sun/plar night and places that don't quite make the cut. There are [lots of calculations involved]http://lakewoodhiker.blogspot.com/2017/03/the-arctic-circle.html), but the takeaway is that the Arctic circle is currently shrinking, moving a small amount of feet or even yards every year.
Lowbush blueberries and crowberries dot the mossy expanse.
These western science delineations of the Arctic are dynamic, contradictory, and imperfect. For Arctic Indigenous peoples such as the Inuit or Sami, the homelands that they know don't often fit neatly within those lines. Their Arctic is informed by knowledge of place passed down and adjusted across generations of living in a place. Around the world, what comprises the Arctic is also influenced by cultural, social, economic, and political factors. So, "Where exactly is the Arctic?" This is a good question!
What questions do you have about the Arctic? Submit them in the comments before my departure day (this Friday, September 20!) so I can take them to the Arctic.
The beautiful foliage of a lowbush blueberry, with the city of Tromso beyond.
Education Extension This geography lesson from Polar Bears International is a great way to introduce upper elementary and middle school students to different ways of defining the Arctic.
For those that live near mountains with low-elevation tree lines (or for those that want to do a more ambitious hike with learners!), hiking from forested areas through the tree line to alpine is a vertical way of simulating the shift from boreal forest to tundra. Have learners use photography, sketching, notes, or quantitative data collection to observe differences in plant and animal life, soil types, temperature, and so on in the different ecosystems.
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