What If Gone

Species → Norway Lemming

Norway Lemming

Lemmus lemmus

population highly variable from year to year; no meaningful global…
Extinction risk Least Concern
Predator-prey cycleArctic environmentClimate changeKey prey
Norway Lemming (Lemmus lemmus)
Photo: Lakkahillo, Wikimedia Commons (CC BY-SA 3.0)

What if it disappeared?

Impact Moderate
Over 37 years (Norway)

The historic 3-to-5-year cycle of lemming booms and busts has faded into a random, low-amplitude pattern, explainable and predictable from increasingly mild winters: warming favors the formation of ice layers at the base of the snowpack, which deprives lemmings of the space beneath the snow where they breed in winter.

Documented
Detail

Kausrud, K., Mysterud, A., Steen, H. et al. (2008). Linking climate change to lemming cycles. Nature, 456, 93–97.

The study combines nearly 40 years (1970–2007) of rodent density data, bird density data, and field measurements of snowpack condition with weather data. At Finse, Norway, the increasing frequency of ice layers at the base of the snow coincides directly with the observed dampening of the cycle — one of the most directly measured links between climate warming and the breakdown of a classic predator-prey cycle.

Over several decades

The dampened cycle deprives the Norwegian Arctic fox — already critically endangered after decades of historical overhunting — of the bumper years it relied on to breed en masse; in lemming-poor years, predators shift more toward the eggs of ground-nesting birds, a mechanism known as the alternative prey hypothesis.

Extrapolated
Detail

Extrapolation à partir de Ims, R.A. et Fuglei, E. (2005). Trophic Interaction Cycles in Tundra Ecosystems and the Impact of Climate Change. BioScience, 55(4), 311–322, et de la littérature de conservation sur le renard arctique norvégien.

The decline of the Norwegian Arctic fox is primarily due to decades of overhunting for fur in the 19th and early 20th centuries, long before the dampening of the lemming cycle was documented. The conservation literature cites the dampened cycle as a compounding factor that complicates the species' natural recovery despite decades of legal protection — a compounding factor, not the original cause.

What's missing to confirm it: The precise share attributable to the dampened lemming cycle, relative to historical overhunting and other factors, in the Norwegian Arctic fox's difficulty recovering naturally despite decades of protection, remains to be quantified.

Documentation

Last verified: August 14, 2026