Climate Zones and Biomes

Arid climates cover about 14% of the Earth. This climate is primarily defined by its lack of precipitation. The annual average amount of precipitation recorded is around 10 inches. Global wind patterns are the main cause of the limited rainfall. However, an arid climate can be a hot desert such as the Sahara Desert in North Africa or a cold desert like the Gobi in China and Mongolia.

Temperate climates are found between the tropical and polar regions in the mid-latitude areas. This climate zone is known to have a wide temperature range as well as distinct seasonal variations. The temperate climate zone can also be influenced by size of the landmass, elevation, sea and wind currents. Much of the southeast United States lies in a temperate climate zone.

The Continental climate zone is mostly found in the mid-latitude regions of the Northern Hemisphere. These regions are generally large land masses with prevailing winds, and are not influenced by bodies of water.

These regions tend to have hot summers and cold winters. The majority of the precipitation in these regions falls during the warmer months, as the area experiences variable weather patterns and temperature variations.

Finally, Polar climate regions are located near the North and South Poles. These areas can be characterized by their cool summers and frigid winters. In fact, the warmest month in this region rarely has an average temperature above 50° Fahrenheit.

Biomes

There are both terrestrial biomes (on land) and aquatic biomes (in water) and each can be broken down further. Geographers have not come to an agreement on the number of biomes. Some define seven while others argue that there are more. Here, we will review seven biomes, including: tundra, taiga, temperate forest, tropical rainforest, grassland, savanna, and desert.

Tundra - The tundra biome is found mainly in the polar regions and at high elevations. The tundra is known for large stretches of bare ground and rock with sparse vegetation due to a short growing season.

With low annual temperatures, the soil may experience permafrost, or stay permanently frozen, which will not allow deep roots to take place. This biome only receives 6-10 inches of precipitation annually which contributes to low and sparse vegetation.

Despite the sparse vegetation, this biome is often home to polar bears, musk oxen, caribou, artic foxes, and hares. The tundra biomes cover about 10% of the Earth’s surface.

Temperate Forest - This biome is the most common found in eastern North America, Western Europe, Eastern Asia, Chile, and New Zealand. Temperatures range from -22°-86°F, depending on the season. Deciduous broad-leaf trees are the dominant form of vegetation in this biome with fewer evergreen trees than in the taiga.

Temperate forest biomes are exposed to both warm and cold air masses which cause the region to experience all four seasons. Many of the same animals found in the taiga also occupy the temperate deciduous forest as well as deer, bald eagles, and in some places monkeys and pandas as well.

Taiga - Sometimes known as "boreal forest", the taiga spans subarctic and northern temperate regions.

The sun never actually reaches directly overhead as it does in warmer areas, contributing to the primary form of vegetation being coniferous evergreen trees such as pines, spruce, and firs.

Bears, gray wolves, elk, and moose are examples of the animals that can be found in this cold biome.

Tropical Rainforest - These biomes are located close to the equator and on average receive between 8-15 feet of rainfall each year.

Tropical rainforests receive 11-12 hours of sunshine a day with average temperatures ranging from 68°-93°F. This contributes to them being the most diverse biomes in the world. About half of all plant and animal species on Earth live in tropical rainforests, despite them just covering 6% of the world’s surface. Animals found in tropical rainforests include jaguars, anacondas, poison dart frogs, toucans, and chimpanzees.

Grassland - These grasslands are also known as prairies and are found throughout central North America and in Eurasia, where these biomes are called steppes. The climate in this biome is usually semi-arid, receiving between 10-35 inches of rain. This lack of rainfall makes the soil insufficient to grow trees and therefore home to large open areas dominated by grasses. These biomes are often used by humans for agricultural purposes, and grazing herd animals such as the American bison and wild horses, as well as prairie dogs and gophers.

Savanna - Savanna biomes are grasslands with scattered trees and are usually found near hot tropical areas. These biomes can be found in Africa, South America, and Asia and have an average temperature ranging between 75°-84°F.

These regions have distinct wet and dry seasons with extensive periods of drought that can result in fires. Grazing herd animals such as elephants, zebras, and giraffes can be found in this biome as well as predators such as lions, cheetahs and hyenas.

Desert - These biomes are usually found on the downwind side of a mountain range. This causes a rain shadow in which the winds drop most of the rain on the mountains leaving the deserts with an average annual rainfall on less than 12 inches a year. These are how the Mojave and Sonoran deserts in North America were formed.

Other deserts, such as the Sahara and Namib deserts in Africa, were formed by the dry air that descends at their latitude. Due to the lack of precipitation, there is little water vapor in the air to trap the temperature. This causes wild swings in which temperatures can reach as high as 140°F during the day and near freezing at night. Plants such as cactuses and succulents as well as animals like camels, bighorn sheep, and the desert tortoise have all learned to adapt to these harsh conditions.

Each biome is intricately linked to the climate zone in which it is located. Studying the relationship between climate zones and biomes is essential for understanding the biodiversity and ecological dynamics that define our planet. Furthermore, learning how human activities such as deforestation, urbanization, and pollution alter climate patterns and shifts in biomes is essential to maintain the Earth’s balance.