Greenhouse effect and global warming
- ICSE Class 10, Unit 6 Environmental concerns & Pollution
The greenhouse effect is the trapping of the Earth's heat by gases such as carbon dioxide and methane; more of these gases causes global warming.
Sunlight passes through the air and warms the ground. The warm ground gives off heat. Greenhouse gases soak up some of this heat and keep it near the surface. Without them, the Earth would be too cold for most life.
Burning coal, oil and petrol, and cutting down forests, add more carbon dioxide to the air. More heat is trapped, and the Earth's temperature rises. That rise is global warming. It melts ice, raises sea levels and changes rainfall.
CFCs, or chlorofluorocarbons, are gases once used in fridges and sprays. They trap heat too, and they also thin the ozone layer, which shields us from the Sun's ultraviolet rays.
A small example
A car parked in the sun with its windows shut gets hot inside. Light gets in, but heat cannot get out easily. Greenhouse gases act a little like the car's glass.
Where marks go
The ICSE 2027 specimen paper describes years of irregular rainfall, crop failure and water shortage. Its answer is climate change. Acid rain and soil erosion are offered as wrong options.
The 2025 ICSE Biology paper asked for the full form of CFC. CISCE's report on the 2025 ICSE Biology paper names "compressed fluorocarbons" as an incorrect expansion. Learn each short form in full.
Sources
Facts last checked against these sources on 30 September 2026.
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