Cold Environments

Brrr! Did someone just turn down the thermostat? Nope - we're taking a look at cold environments! We all know certain areas of our planet are cold, but what constitutes a cold environment, and where exactly are they located? Some of these areas are gradually disappearing, but you still might want to bundle up for now.

Physical characteristics of cold environments

Cold environments are typically rocky, mountainous, and/or barren. Cold environments are defined more by what they lack rather than what they have. Only the toughest plants and animals can survive in them. Therefore, cold environments generally have less biodiversity than other areas of the world.

In some cold environments, ice covers the ground for the entire year. This may even manifest as permafrost, ground that is at or below 0°C (32ºF) for at least 2 consecutive years, but more often than not, it is permanently frozen ground. Icy ground coverage makes it difficult for larger plants like trees to grow, so some of the most common plants found in cold environments are mosses.

Types of cold environments

To further break this down, cold environments can be divided into four major categories based on their specific physical characteristics. These four categories are alpine, glacial, periglacial, and polar environments.

Alpine

Alpine environments are cold environments associated with mountainous regions and are characterised by a lack of trees and other woody vegetation. The disappearance of trees at the boundary of an alpine environment is sudden. It is referred to as the tree line, meaning that alpine environments are considered to be above the tree line. Instead of trees, the ecological communities are dominated by grasses and other non-woody flowering plants.

The image below shows an alpine environment in Switzerland, including a very noticeable transition in the environment via the tree line.

Fig. 1 - Alpine environment in St. Moritz,

Glacial

A Glacial Environment is associated with glaciers and is dominated by glacial processes (the movement of large volumes of ice) shaping and reworking the land. These environments are typically located in mountainous regions (e.g. the Alps, Andes, or the Himalayas) or within the Arctic/Antarctic; they rely on winter accumulation of snow and ice following the retreat of the ice during the summer. Glacial environments cover the smallest area of the globe out of all the different categories of cold environments and are usually found in high elevation regions.

Check out our explanations on Glacial Movement, Glacial Landforms, and Glacial System to learn more!

Periglacial

Periglacial Landscapes can be quite similar to glacial environments but are shaped by freeze-thaw Periglacial Processes, which involve the repeated annual melting and formation of ground ice. They are located on the boundary of polar and glacial environments, covering an estimated 25% of the Earth’s land surface, and can be found across the Earth.

Polar

Polar regions are similar to alpine environments, characterised by the lack of any major temperature increase during the summer leading to a lack of trees and other woody vegetation. This means polar regions are also above the tree line. But unlike alpine regions, which are created through elevation, polar conditions are created by latitude. Polar environments are divided into two major categories: tundra and ice cap environments.

In tundra regions, at least one month of the year has an average temperature above zero degrees Celsius. This allows grasses, mosses, and other plants specialised for the cold to exist. On the other hand, an ice cap is a polar region where the temperature never goes above the point of freezing, meaning no plant life survives on the surface.

Distribution of cold environments

As we mentioned above, the distribution of cold environments globally is largely dependent on two factors: elevation and latitude.

The elevation is usually measured as height above sea level. The higher up you go from the sea, the colder things tend to get. This is because the atmosphere is thinner at higher elevations, meaning there is less heat energy. The elevation is the major determining factor in the existence of alpine environments, which are associated with mountains.

Fig. 2 - The Earth gets colder farther from the equator

Latitude is a way of measuring the distance from the equator, an imaginary line surrounding the Earth's centre. You can think of latitude as rungs on a ladder, with the equator in the exact middle. Because of the spherical shape of our planet, the equator receives more sunlight than anywhere else and is, therefore, on average, the warmest part of the Earth. The further we are from the equator, the colder things tend to get - until we arrive at the extreme northernmost and southernmost latitudes, which are regions known as the Arctic and Antarctic, respectively. These areas are also known as the North and South Poles (and thus, polar regions are associated with latitude).

Location of cold environments

The global patterns of cold environments are influenced by more than just elevation or latitude. If that's all there was to it, there would be distinct latitudinal bands for the boundaries of cold environments. Instead, multiple other factors also affect the distribution of cold environments across the planet.

Oceans act to regulate temperature fluctuations both on annual and seasonal scales. This means that the further you move away from the coast, the more extreme temperature changes can occur. This is why periglacial environments appear further south in Russia and Canada than in other regions at similar latitudes like Scandinavia.

Another major factor is both atmospheric and oceanic circulation currents. The gulf stream, a warm oceanic current originating from North America, which travels to northwestern Europe, creates warmer climatic conditions in northwest Europe, preventing Scandinavia from experiencing polar, periglacial, or glacial conditions.

Looking at the global distribution of cold environments, most of these landscapes are located near the North and South Poles. Periglacial environments are the most widespread (by surface area) type of cold environment, with vast stretches situated in North America and northern Eurasia. Polar regions are the second most widespread, being located within the Arctic and Antarctic circles. Alpine environments are restricted to high elevation regions and therefore are only found on mountainsides across the Earth. Lastly, glacial environments have the most restricted range of all cold environments, though they can be found globally in mountainous and polar regions.

Cold environments map

While it is difficult to illustrate every single instance of an alpine environment on a global scale, it is possible to map out cold environments latitudinally generally. In the map below (figure 3), the blue colour highlights areas that are permanently cold environments. As you can see, the coldest environments are located at the poles, but they aren't simple straight lines across the map due to oceanic and atmospheric forces.

Threats to cold environments

With the encroachment of climate change and global warming, it is expected that, in the near future, cold environments will change dramatically. However, it is not realistic to assume that the average temperature of all cold climates will increase due to global warming. As previously mentioned, air/oceanic currents play a major role in shaping climatic conditions. Therefore, coupled with climate change, changes in these currents may cause some regions to experience a drop in temperature.

Climate change is also thought to increase the likelihood and magnitude of atypical or extreme weather events, such as the snowstorm that reached Texas in February of 2021. In regards to cold environments, this will decrease the climatic stability of these regions, changing the way the landscape-changing processes will function. This is why climatic models and simulations are important in better predicting the changes that will occur in the future.

The increase in global average temperatures is still a major threat to cold environments. The warming effect associated with climate change projections is thought to be concentrated in the planet's polar regions.

Cold environments play an important role in regulating the Earth’s climate through the storage of a lot of carbon in the form of permafrost in periglacial regions, and through ice reflecting more of the sun’s energy back into space than either bare ground or seawater (a phenomenon known as the albedo effect). If the threat to cold environments posed by climate change leads to their shrinkage, it will mean that warming will continue to escalate with no natural processes to help mitigate the warming effects across the rest of the planet. This is why cold environments need to be protected.

In addition to regulating climate, many species of both plants and animals are specially adapted to cold environments. With the disappearance of reduction of these habitats, those species will be under the imminent threat of extinction.