The correct option is (b).
Explanation
Global Warming refers to the long-term rise in the average temperature of the Earth's climate system, primarily observed since the pre-industrial period (between 1850 and 1900).
- Statement 1 is Incorrect: Global warming is caused by an increase in the concentration of greenhouse gases, particularly Carbon Dioxide ($CO_2$), in the atmosphere. These gases trap heat radiating from Earth toward space (the Greenhouse Effect), rather than allowing it to escape. A decrease in $CO_2$ would theoretically lead to cooling, not warming.
- Statement 2 is Correct: The accumulation of greenhouse gases enhances the atmosphere's capacity to retain heat, leading to a measurable increase in global average temperatures. This warming drives changes in weather patterns and climate systems.
- Statement 3 is Incorrect: Global warming is directly linked to anthropogenic (human-caused) activities. Emissions from industries (burning fossil fuels for energy) and vehicles (internal combustion engines releasing $CO_2$) are among the primary contributors to the increased levels of greenhouse gases in the atmosphere.
Key Takeaway: Global warming is the phenomenon of rising average global temperatures caused by the enhanced greenhouse effect resulting from the accumulation of emissions like Carbon Dioxide from human activities such as industrial production and transportation.