The nature and distribution of cold environments

Welcome to the Freezer! Understanding Cold Environments

Hello there! Welcome to your study notes for AQA AS Geography (7036). In this chapter, we are exploring one of the most extreme and beautiful parts of physical geography: Cold Environments.

Don't worry if this seems a bit "chilly" at first! We are going to break down where these places are, what they look like, and why they are the way they are. Think of this as getting a VIP tour of the Earth's freezer. Let’s dive in!

1. What Exactly is a "Cold Environment"?

A cold environment isn't just a place where you need a coat. In geography, these are specific areas where the temperature stays at or below 0°C for a significant part of the year. Because it's so cold, ice and snow are the main characters in these landscapes.

The syllabus breaks these down into four main types. A great way to remember them is that they are defined by Latitude (how far north/south they are) or Altitude (how high up they are).

The Four Types of Cold Environments

1. Polar Environments: These are found at the very top (North Pole/Arctic) and very bottom (South Pole/Antarctica) of the world. They are the "extreme" version—very cold, very dry, and mostly covered in massive ice sheets.
Example: Antarctica.

2. Alpine (Montane) Environments: These are high-altitude mountain areas. Even in warm countries, if you go high enough, it gets cold! This is why you can see snow on mountains in Africa.
Example: The Alps or the Himalayas.

3. Glacial Environments: These are specific areas actually covered by glaciers (rivers of ice) or ice sheets. They can be found in polar or alpine regions.
Example: The Franz Josef Glacier in New Zealand.

4. Periglacial Environments: The word "peri" means "around." So, these are areas around the edges of glacial or polar regions. It’s cold enough for the ground to be frozen, but not always covered in ice. They are famous for tundra vegetation.
Example: Northern Canada or Siberia.

Quick Review Box:
Polar = High latitude (the poles).
Alpine = High altitude (mountains).
Glacial = Places with actual ice masses.
Periglacial = Places "near" ice with frozen ground.

2. Physical Characteristics: Climate, Soils, and Vegetation

In cold environments, everything is connected. The climate dictates the soil, and the soil dictates what can grow.

Climate: The "Freezer" Effect

The climate is defined by two things: Low temperatures and low precipitation (rain/snow).
- Polar regions are often "cold deserts." Because the air is so cold, it can't hold much moisture, so it rarely snows heavily.
- Alpine regions might have more snow because mountains force air to rise and cool (this is called orographic rainfall).

Soils: Permafrost and Peat

In periglacial areas, we find Permafrost. This is ground that has been frozen for at least two years straight.
- The Active Layer: In summer, the very top bit of soil melts. It becomes soggy and "soupy" because the water can’t drain away through the frozen ice below.
- Nutrients: Because it’s so cold, dead plants don’t rot quickly. This means the soil is often thin and lacks the nutrients needed for big trees to grow.

Vegetation: Living on the Edge

Plants here have to be tough! You won't find oak trees or roses. Instead, you find:
- Lichens and Mosses: These can grow on bare rock.
- Low-lying shrubs: Plants stay close to the ground to avoid the freezing, biting winds (think of it like "hugging" the Earth for warmth).
- Rapid life cycles: Plants flower very quickly during the short summer when the active layer of soil thaws.

Did you know? Some plants in cold environments have "anti-freeze" in their sap to keep their cells from bursting when it freezes!

Key Takeaway: Cold environments have extreme climates (cold/dry), frozen soils (permafrost), and small, hardy plants that hunker down to survive the wind.

3. Global Distribution: Past and Present

Where are these cold places? The answer depends on whether you are looking at a map today or a map from thousands of years ago!

Present Distribution

Today, cold environments cover about 20% of the Earth's land surface.
- Ice Sheets: Only two remain today—Antarctica and Greenland.
- Periglacial/Tundra: Large parts of Northern Russia (Siberia), Canada, and Alaska.
- Alpine: The "spine" of major mountain ranges like the Andes, Rockies, and Himalayas.

Past Distribution: The Pleistocene Glaciations

Geographers love to talk about the Pleistocene. This was a geological epoch that lasted from about 2.6 million years ago until 11,700 years ago. During this time, the Earth went through several "Ice Ages" (glacials) and warmer periods (interglacials).

At the height of the last Ice Age (the Last Glacial Maximum):
- About 30% of the Earth was covered in ice.
- Massive ice sheets reached down into the Midwest of the USA and as far south as London in the UK!
- Because so much water was frozen into ice on land, sea levels were much lower than they are today.

Analogy Time!
Think of the Pleistocene like a very long winter where the "ice sheet blanket" kept being pulled down over the Earth's shoulders, then pushed back up, then pulled down again. Today, we are in a warm "morning" period where the blanket has been kicked to the bottom of the bed (the Poles).

Common Mistake to Avoid: Don't assume the UK is a "glacial environment" today. It was a glacial environment in the past. Today, the UK only has very small periglacial characteristics in the high Scottish Highlands.

Summary Checklist: The Nature and Distribution of Cold Environments

- Definitions: Can you explain the difference between Polar, Alpine, Glacial, and Periglacial?
- Climate: Do you remember that they are often "cold deserts" with low precipitation?
- Soils: Do you know what Permafrost and the Active Layer are?
- Vegetation: Can you name two adaptations (e.g., growing low to the ground)?
- Distribution: Can you name the two current ice sheets (Antarctica/Greenland) and explain that ice covered much more of the world during the Pleistocene?

Well done! You've just covered the foundations of Glacial Systems and Landscapes. Keep this "big picture" in mind as you move on to learning about how that ice actually moves and carves out the land!