C.1.2 Relief and Climatic Characteristics Notes

Factors Contributing to Extreme Conditions

1. Extreme environments can be broadly categorized into two types:
2. Cold and high-altitude environments
3. Hot and arid environments.

Cold and High-Altitude Environments

1. Low Temperatures

Temperature Gradient with Altitude:

1. Temperatures decrease by approximately 6.5°C per 1,000 meters of elevation.
2. This is due to the thinning of the atmosphere, which reduces its ability to retain heat.

Polar Regions:

1. Temperatures can drop below -50°C due to the tilt of the Earth, which limits solar energy reaching these areas.

Example

In the Himalayas, temperatures can plummet to -20°C or lower at high altitudes, while in Antarctica, winter temperatures fall below -60°C.

2. High Winds and Snow/Ice Accumulation

Wind Chill:

1. High winds amplify the cold, making it feel much colder than the actual temperature.

Snow and Ice:

1. Snow and ice accumulation creates hazardous conditions, such as avalanches and glacial movement.

3. Limited Oxygen at High Altitudes

Reduced Atmospheric Pressure:

1. At high altitudes, the air is thinner, meaning less oxygen is available for breathing.

Physiological Stress:

1. This causes altitude sickness, which includes symptoms like headaches, dizziness, and fatigue.

4. Short Growing Seasons and Poor Soils

Cold Climates:

1. Growing seasons are brief, with temperatures above 6°C for only a few months.

Soil Conditions:

1. Soils are often thin, infertile, and prone to erosion.

Hot and Arid Environments

1. High Temperatures and Intense Solar Radiation

Temperature Extremes:

1. Daytime temperatures can exceed 50°C, while nights are much cooler due to the lack of moisture in the air and limited cloud cover, which reduces heat retention.

Solar Radiation:

1. Intense sunlight increases the risk of heatstroke and dehydration.

Example

In the Sahara Desert, temperatures can reach 58°C, making it one of the hottest places on Earth.

2. Low Humidity and Water Scarcity

Minimal Rainfall:

1. Deserts receive less than 250mm of rain annually, with some areas experiencing years without precipitation.

High Evaporation Rates:

1. Any available water quickly evaporates, exacerbating drought conditions.

3. Unreliable and Infrequent Rainfall

Water Scarcity:

1. Long periods without rain are common, leading to severe water shortages.

Flash Floods:

1. When rain does occur, it often falls in short, intense bursts, causing flash floods due to the hard, compacted soil.

4. Poor Soil Quality

Thin and Nutrient-Poor Soils:

1. Desert soils are often sandy or rocky, lacking the nutrients needed for plant growth.

Salinization:

1. High evaporation rates can lead to salt accumulation in the soil, further reducing fertility.

Why Do These Conditions Matter?

Human Challenges:

1. Extreme environments significantly hinder human habitation, agriculture, and infrastructure development.

Ecological Impacts:

1. These conditions shape unique ecosystems that are highly sensitive to changes, such as climate change or human intervention.

1. Understanding the factors that contribute to extreme conditions helps us appreciate the resilience of life in these environments and the challenges faced by those who inhabit them.