Ch 17World Climate and Climate Change — Class 11 Geography, concept-first.

World climate is far too vast and varied to describe one place at a time. To make it manageable, geographers study climate by organising the enormous amount of information and data available and synth…

Koeppen identified a close relationship between the distribution of vegetation and climate, and used this link to build his classification.

The tropics are the belt of the Earth that lies between the Tropic of Cancer and the Tropic of Capricorn.

A dry climate is defined not by heat but by a shortage of water. The book’s core idea: rainfall is so low that it cannot support the growth of plants.

Warm temperate (mid-latitude) climates sit between roughly 30° and 50° of latitude, mostly along the eastern and western margins of continents.

Cold snow forest climates are the climates of the vast northern interiors of continents — places where winter is long, dark, and bitterly cold, and where the forest that grows is the boreal or taiga f…

Polar climates are found poleward of 70° latitude. The defining feature is extreme cold throughout the year, with temperatures that never rise high enough to support trees.

Climate is the long-term average of weather conditions, but the world's climates are so varied that studying them requires organisation.

Climate is never perfectly stable — it keeps varying, and the recent past gives us plenty of evidence.

The causes of climate change are many, and they fall into two broad groups: astronomical and terrestrial.

The atmosphere, because of certain gases, behaves like a greenhouse. It lets sunlight in but traps much of the heat the Earth sends back out.

The greenhouse gases that matter most today are carbon dioxide, chlorofluorocarbons, methane, nitrous oxide and ozone.