Two Climates In One
There are two general types of polar climate:
• The “ice-cap” or “perpetual frost” climate, which has sub-freezing temperatures all year.
• The tundra, where at least one month’s average temperature is above freezing.
To complicate matters further, tundra comes in three flavors: Arctic, Antarctic, and Alpine tundra, which is found in mountainous terrain where cold temperatures are due to high elevation regardless of latitude.
Antarctica is the only continent on earth where a polar climate dominates. The Arctic is more diverse.
In the Arctic, tundra is found in the southern regions, and ice caps are further north. A lot of the Arctic region is permanently covered by solid or drifting pack ice. That permanent ice is a 3 to 4-meter thick ice sheet covering approximately 8 million square kilometers north of Svalbard and Franz Josef Land. It’s tough to impossible for plants and animals to live under that polar ice, considering very little sunlight penetrates through to the water. Only a few species inhabit the very far north.
Tundra covers most of northern Canada and Alaska, parts of northern Siberia, northern Iceland, and the extreme northeastern coast of Scandinavia east to the Bering Strait. Tundra is known for its low temperatures and short growing seasons – that means no (or very few) trees grow there. Grasses, mosses and lichens are the big three in the Arctic tundra. Plants are very slow-growing and long-living. They are stunted in size compared to their warm-weather relatives. Even the tiniest plants can be incredibly old.
Year-round permafrost means that the ground material stays at or below freezing for two or more years. Ice doesn’t have to be present, though it often is. An active layer of ground on the surface (on top of the permafrost) that thaws seasonally during the short summer can support plant life.
Typically, ground temperature varies less than air temperature from season to season. Temperatures are also colder the deeper you go into the ground. In some of the “warmer” climates, where air temps hover just below and around freezing, you see discontinuous permafrost. That means permafrost only forms in sheltered areas that often face north, so there are patches of permafrost that might not go very deep under the surface.
[TRIP TRIVIA: Want to take world-class wildflower photos? Go to the Arctic! Though they bloom fast to take advantage of the condensed summer sunshine, there are over 300 species of low-growing flowering plants. Compare that to only two flowering species in Antarctica!]
In polar language, an ice cap is a dome-shaped ice mass that covers less than 50,000 square kilometers of area, usually on a mountain or at high altitude. If the ice covers more than 50,000 km2, it’s called an ice sheet.
In many Canadian dialects, an ice cap is an iced cappuccino – a fun and frothy drink of the coffee variety that comes in mugs small enough to wrap your fist around. While standing on a polar ice cap, a hot cap(puccino) might be more appropriate.