An Arctic Climate Laboratory
In the vast expanse of the Northeast Greenland National Park—the largest national park in the world—lies the Zackenberg Valley. This high-Arctic valley is a polar semi-desert, characterized by a mean annual temperature of -8.7°C and just 253 mm of annual precipitation. The entire landscape is underlain by continuous permafrost, with only the top 20 to 100 cm of soil, known as the active layer, thawing during the brief summer. This active layer is deepening by an average of 0.74 cm per year, a direct indicator of a warming climate.
In the valley is the Zackenberg Research Station, established in 1995 to conduct long-term monitoring of this sensitive ecosystem. A comprehensive program called Greenland Ecosystem Monitoring (GEM) tracks everything from climate and geology to the life cycles of plants and animals. The station operates several sub-programs, including ClimateBasis, GeoBasis (monitoring carbon balance and permafrost), and BioBasis (monitoring flora and fauna). Data from Zackenberg is a baseline for understanding how untouched Arctic environments respond to rapid climate change. Research here shows that while temperatures are rising, the onset of spring has become highly variable, shifting from a trend of progressively earlier springs to a pattern of extreme seasonal swings year to year.
A Race Against the Cold
Life in Zackenberg Valley is compressed into a frantic burst of activity during a growing season that can be as short as 60 days. With the ground covered by snow for about 236 days a year, the timing of the snowmelt is the single most important factor for all life. Plants must sprout, flower, and set seed in this narrow window. To get a head start, many species like the Arctic bell-heather (Cassiope tetragona) develop their flower buds a full year in advance, ready to blossom the moment the snow disappears.
The valley supports a surprising diversity of life adapted to these harsh conditions. It has a large population of muskoxen (Ovibos moschatus), which are closer related to sheep and goats than to oxen. These Ice Age survivors, called "Umimmak" or "the long-bearded one" in Greenlandic, feed on sedges, willows, and flowers. Other resident mammals include the collared lemming (Dicrostonyx groenlandicus), the Arctic fox (Vulpes lagopus), and the Arctic hare (Lepus arcticus), while polar bears and Arctic wolves are occasional visitors. The food web is tightly synchronized. The emergence of insects, for example, must align perfectly with the flowering of plants and the arrival of migratory birds that come to nest and feed on the brief abundance of food.