Answer: Greenhouse Effect - Causes and Effects
Greenhouse Effect is the natural process by which certain gases in Earth's atmosphere trap infrared radiation (heat) from the Sun, warming the planet's surface. Without it, Earth would be -18°C instead of +15°C. The problem is the enhanced greenhouse effect caused by human activities.
Causes of Enhanced Greenhouse Effect
1. Emission of Greenhouse Gases
- CO2 (76%): Fossil fuel combustion, deforestation, cement production
- Methane (16%): Agriculture, livestock, landfills, natural gas leaks
- Nitrous Oxide (6%): Fertilizers, industrial processes
- F-gases (2%): Refrigeration, air conditioning
2. Human Activities
- Burning Fossil Fuels: Power plants, vehicles, industries (~75% of emissions)
- Deforestation: Removes carbon sinks, releases stored carbon
- Agriculture: Rice paddies, livestock, fertilizers
- Industrial Processes: Cement, steel, chemical manufacturing
CO2 Rise: From 280 ppm (pre-industrial) to 420+ ppm today - a 50% increase
Effects of Greenhouse Effect
1. Global Warming
- Earth's temperature increased by ~1.1°C since pre-industrial era
- More frequent and intense heat waves
- Projected 1.5-4.5°C rise by 2100
2. Climate Change
- Changed precipitation patterns - floods and droughts
- More intense cyclones and storms
- Erratic monsoons in India
3. Melting Ice and Sea Level Rise
- Arctic sea ice declining rapidly
- Glaciers retreating globally (including Himalayas)
- Sea level rising ~3.7 mm/year - threatens coastal areas
4. Ecosystem Impacts
- Coral bleaching due to ocean warming
- Species migration and extinction
- Ocean acidification harming marine life
5. Human Impacts
- Reduced agricultural productivity
- Water scarcity in many regions
- Health impacts - heat stress, disease spread
- Climate refugees and migration
Conclusion
The enhanced greenhouse effect, caused by human emissions of CO2, methane, and other GHGs, is driving global warming and climate change. Effects include rising temperatures, extreme weather, sea level rise, and ecosystem disruption. Urgent action through emission reduction, renewable energy, and afforestation is needed to limit warming to 1.5°C as per the Paris Agreement.
Sources: Module 1 Notes | IPCC AR6