- A Natural volcanic activity releasing large quantities of ash and sulfur aerosols into the stratosphere
- B Enhanced greenhouse effect from human-generated greenhouse gases, primarily CO2 from fossil fuel burning
- C Ozone layer depletion occurring largely without any significant contribution from other greenhouse gases
- D Cyclical variation in solar radiation output occurring naturally over multi-decade and centurial timescales
Correct answer: B. Enhanced greenhouse effect from human-generated greenhouse gases, primarily CO2 from fossil fuel burning
Explanation: Global warming is caused by the enhanced greenhouse effect due to human activities: fossil fuel combustion (CO2), deforestation, agriculture (CH4 from livestock, N2O from fertilizers). Global average temperature has risen ~1.1 degrees C since pre-industrial times. Scientific consensus: >97% of climate scientists agree on human causation.
Concept context
Pollution, global warming, ozone depletion, deforestation, and sustainability. Important for NEET and general awareness.