World Climate and Climate Change| Class 11 Geography Notes (original) (raw)
Last Updated : 23 Jul, 2025
The **world climate is a broad system that can be influenced by different factors including changes in the composition of the atmosphere, solar radiation, ocean currents, greenhouse gases, human-made pollution, and related activities. Koeppen described the close connection between the climate distribution and the vegetation present on Earth. The classification helps us to understand the climate of the Earth with a set of data of the monthly and annual averages of precipitation and temperature of a specific location.
In this article, we are going to discuss the World Climate and Climate Change in detail.
World Climate and Climate Change| Class 11 Chapter 11
Koeppen Scheme of Classification of World Climate
The Köppen climate classification system is one of the most common and efficient systems in the world. It is mainly used for classifying the climate into five groups. The division is based on the temperature, precipitation, and local vegetation. There are five groups in this classification tropical, dry, mild, continental, and polar. Each group is further divided into different climate types. Each group and subgroup is represented by a letter. Let us discuss this in detail.
- The first letter of the classification indicates the climate group, and the second letter indicates the season.
- Type A climates focus on the seasonality of their precipitation.
- The Köppen classification also includes midlatitude C and D climates.
- These climates are given a second letter, which can be f, w, or s. F indicates no dry season, w indicates winter dry, and s indicates summer dry.
- The Köppen classification also includes a third symbol, which can be a, b, c, or d.
- The last subclass only exists for D climates and indicates summer warmth or winter coldness.
Climate Category
The Koeppen climate classification system recognizes five major climatic types and each type is designated by a capital letter- A, B, C, D, E, and H.
| Group | Type | Letter code | Characteristics |
|---|---|---|---|
| A-Tropical Humid Climate | Tropical Wet Tropical Monsoon Tropical wet and dry | Af Am Aw | No dry season Monsoonal, Short dry season Winter dry season |
| B-Dry Climate | Subtropical Steppe Subtropical Desert Mid-latitude Steppe Mid-latitude Desert | BSh BWh BSk BWk | Low-latitude semi-arid or dry Low-latitude arid or dry Mid-latitude semi-arid or dry Mid-latitude arid or dry |
| C-Warm temperate Climates | Humid subtropical Mediterranean Marine west coast | Cfa Cs Cfb | No dry season Dry hot summer No dry season, warm and cool summer |
| D-Cold Snow-forest Climates | Humid Continental Subarctic | Df Dw | No dry season, severe winter Winter dry and very severe |
| E-Cold climates | Tundra Polar ice cap | ET EF | No true summer Perennial ice |
| H-highland | Highland | H | Highland with snow cover |
Season Type
The Köppen climate classification system divides climates into five main groups based on seasonal precipitation and temperature patterns.
| Season Type | Description |
|---|---|
| f | No dry season |
| m | Monsoon climate |
| w | Winter dry season |
| s | Summer dry season |
Temperature Severity
The Köppen climate classification system uses different temperature severity. It helps to indicate the severity of the winter. The small letters a, b, c, and d represent the level of heat. The second letter of the system indicates the seasonal precipitation type, and the third letter indicates the level of heat.
| Temperature Severity | Description |
|---|---|
| a | Hot |
| b | Warm |
| c | Cool |
| d | Cold |
Climate Change and Its Impacts
Climate Change is a state of impact that indicates and calculates the increasing the frequency and severity of different natural disasters. Increasing temparature may increase the probability of wildfires which releases so many pollutant in the climate.
Here are the major factors of the Climate Change as mentioned below.
- The ozone layer shields the Earth from harmful UV rays. Ozone hole is a state when this layer thins in the stratosphere.
- Greenhouse gases trap the sun heat by absorbing long wave radiation. It causes the greenhouse effect and contributes in the raising temperature of the Earth.
- Temperature changes drastically impact on the weather and climate.
- Global warming is a situation that is caused by different gases like carbon dioxide, methane, and nitrous oxide. These gases are the main cause of climate change, melting glaciers, and increasing flood risks.
- Heat waves are the another reason of climate change that is caused by industrial emissions.
- Deforestation reduces oxygen levels in the atmosphere. It is the cause of increasing harmful gases and temperature which alters weather and climate.
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