Cold Snow-Forest and Polar Climates (Groups D and E)

At a Glance

• Group D Coldest month below minus 3 degrees Celsius
• Taiga Coniferous forest of Siberia and Canada
• Group E Warmest month below 10 degrees
• ET and EF Tundra and ice cap
• Key issue Permafrost thaw and ice loss
• Exam link UPSC Prelims, Geography: El Niño and Climate Classification

Where Does It Fit?

This is the last topic of the category on El Niño and climate classification and of the macro on the climate system. The previous topic described the dry and the mild climates, and this one completes the Köppen scheme with the coldest groups. The next macro begins the study of the oceans. Previous topic: Dry and Warm Temperate Climates (Groups B and C). Next topic: Major Ocean Relief Features.

What Are the Cold Snow-Forest Climates of Group D?

In short: Group D climates have the most extreme annual range of temperature on Earth, with long, bitter winters and short, warm summers.

Group D is found only in the northern hemisphere, in the interiors and the eastern parts of the great land masses of North America and Eurasia between about 40 and 70 degrees north. There is no Group D in the southern hemisphere, because there is no land mass at those latitudes that is large and far enough from the sea. The distance from the sea produces continentality, with a very large annual range of temperature, as in Horizontal Distribution of Temperature and Latitudinal Heat Balance. The rainfall is moderate, about 40 to 100 cm, mostly in summer from convection, with snow in winter, which comes from temperate cyclones, as in Temperate Cyclones.

The taiga, or boreal forest, is the largest forest biome of the world. The trees are mainly spruce, fir and pine, with needle-shaped leaves and conical shapes that shed snow and conserve water. The soil is a poor, acidic podzol. Verkhoyansk and Oymyakon in northeastern Siberia have a winter minimum near minus 68 degrees Celsius, the lowest temperature of a permanently inhabited place, but a summer that can pass 30 degrees, giving an annual range of well over 60 degrees. In India, the Dfc type is found in a small part of Arunachal Pradesh, as in Köppen Scheme of Climate Classification.

What Are the Polar Climates of Group E?

• Tundra (ET): the warmest month is between 0 and 10 degrees Celsius. It lies along the Arctic coasts of North America and Eurasia and on the fringes of Antarctica and high mountains. The ground is frozen as permafrost, and only the thin surface layer thaws in summer, forming marshes. The vegetation includes mosses, lichens, sedges and dwarf shrubs, and no trees. The Inuit, Sami and Nenets have traditionally hunted and herded reindeer.
• Ice cap (EF): every month is below 0 degrees Celsius, and ice covers the land permanently, as in Greenland and Antarctica. Antarctica is the coldest, driest and windiest continent, with the lowest recorded temperature of about minus 89 degrees Celsius at Vostok, and it holds around 90 per cent of the world’s ice.
• Light and dark: near the poles, the Sun does not set for weeks to months in summer, called the midnight sun, and does not rise in winter, called the polar night. The Sun is always low, and the ice reflects most of the light, which is why the poles are cold, as in Heat Transfer and Heat Budget of the Earth.
• Highland climate (H): the Himalaya and other high mountains have a polar-type climate at the top, with the climate changing with altitude, and the snow line on the Himalaya is at around 4,500 to 5,500 metres.

Why Are the Cold Climates Important Today?

The polar regions are warming faster than the rest of the world. The thawing of permafrost, which contains a large store of carbon, releases carbon dioxide and methane and may speed up warming, and it damages roads, pipelines and buildings built on the frozen ground. The melting of Greenland and Antarctic ice raises the sea level, and the loss of Arctic sea ice opens new shipping routes, such as the Northern Sea Route, and increases competition for resources. Antarctica is governed by the Antarctic Treaty of 1959, which reserves the continent for peace and science, and India has research stations there, Maitri and Bharati, and an Arctic station called Himadri at Ny-Ålesund, Svalbard. As an analytical point, the cold climates are the climate system’s early warning area: what happens to the permafrost and the ice sheets decides the pace of global warming and sea level rise for coastal countries like India. The conclusion of the Köppen scheme is that all climate types are results of the same few controls: latitude, pressure belts, continentality, relief and ocean currents.

Why Is This Topic Important?

• Completes Köppen Groups D and E
• Environment Permafrost and ice melt
• India link Polar research stations

What Came Next?

The next macro begins the study of the oceans, starting with the relief of the ocean floor. Next topic: Major Ocean Relief Features.

Key People and Terms

• Taiga Boreal coniferous forest
• Tundra Treeless polar vegetation zone
• Permafrost Permanently frozen ground
• Midnight sun Sun visible at midnight in summer
• Polar night Weeks of continuous darkness
• Podzol Acidic soil of the taiga

Exam Corner

Mains Angle

Questions link cold climates with climate change. These points add depth.

• Range Continentality
• Permafrost Carbon feedback
• Governance Antarctic Treaty