A polar climate represents the coldest climate zone on Earth, defined by a persistent lack of warmth. These regions are situated at high latitudes, primarily near the North and South Poles, where the sun’s energy strikes the surface at an extremely low angle. This results in an environment dominated by ice, snow, and permafrost, creating a landscape of intense cold that limits plant and animal life.
The Defining Temperature Threshold
The defining characteristic of a polar climate is its inability to sustain a warm season. According to the Köppen climate classification system, a region is designated as polar if the average temperature of its warmest month is below 10°C (50°F). This threshold corresponds to the poleward limit of where trees can grow.
Because no month averages above 10°C, the climate lacks the thermal energy required for extensive plant life. This lack of summer heat prevents the widespread thawing necessary for deep soil development and forest growth. The ground often remains permanently frozen beneath the surface, a condition known as permafrost.
The Two Main Types of Polar Climate
Polar climates are categorized into two subtypes based on the severity of their coldness. The Tundra climate (ET) is characterized by having at least one month with an average temperature above 0°C (32°F), but still below the 10°C threshold. This slight summer thaw allows for the growth of low-lying vegetation, such as mosses, lichens, and dwarf shrubs.
In contrast, the Ice Cap climate (EF) is the most extreme form of cold. In this climate, the average temperature for every month is 0°C (32°F) or below. Because the temperature never rises above freezing, permanent ice and snow cover the surface, preventing vegetation from taking root.
This distinction dictates the landscape and ecology of the region. Tundra regions feature a thin, active layer of soil that thaws in summer, creating marshy conditions on top of the permafrost. Ice Cap regions, like the interior of Antarctica, are dominated by massive, permanent ice sheets that can be kilometers thick.
Extreme Light Cycles and Low Precipitation
Polar climates are defined by dramatic shifts in solar radiation due to their high latitude. The Earth’s tilt results in the phenomenon of the Midnight Sun, where the sun remains visible for 24 hours a day during the summer months. Conversely, the Polar Night occurs in winter, plunging the region into months of continuous darkness as the sun does not rise above the horizon.
The low angle at which the sun’s rays hit the surface limits the amount of solar heating, and the high reflectivity of snow and ice further reduces heat absorption. Polar regions are classified as polar deserts. The air is too cold to hold substantial moisture, resulting in extremely low annual precipitation, often less than 250 millimeters (10 inches).
The moisture that falls is almost always snow, which accumulates over time to form massive ice sheets and glaciers. This aridity means these icy environments receive as little precipitation as the world’s hot deserts.
Where Polar Climates Exist Globally
Polar climates are found at the northern and southern extremes, extending beyond the Arctic and Antarctic Circles. The Ice Cap climate (EF) is most prevalent across the continent of Antarctica and the interior ice sheet of Greenland. These two regions represent the largest expanses of perpetual ice.
The Tundra climate (ET) is found primarily in the Northern Hemisphere, ringing the Arctic Ocean. This includes the northern coastal areas of North America, such as Alaska and Canada, and the northern reaches of Eurasia, including Siberia and Scandinavia. High-altitude peaks of major mountain ranges, such as the Andes and the Himalayas, can also exhibit polar climate conditions due to elevation.