15. Which of the following is a major source of greenhouse gas emissions?

A: Deforestation
B: Wind energy
C: Hydroelectric power
D: Solar energy

To determine which option is a major source of greenhouse gas emissions, we need to understand what greenhouse gases are and how each option contributes to their emissions.

Greenhouse gases are gases that trap heat in the Earth's atmosphere, leading to the greenhouse effect and global warming. Major greenhouse gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).

A: Deforestation - When trees are cut down and burned or left to decompose, they release large amounts of carbon dioxide into the atmosphere. This contributes to greenhouse gas emissions.

B: Wind energy - Wind energy is a renewable and clean source of power that does not directly emit greenhouse gases. Therefore, it is not a major source of greenhouse gas emissions.

C: Hydroelectric power - Hydroelectric power harnesses the energy of flowing water to generate electricity. While it does not directly emit greenhouse gases, the construction and operation of hydroelectric power plants can lead to indirect emissions due to the release of greenhouse gases from the decomposition of flooded vegetation and the production and maintenance of infrastructure.

D: Solar energy - Solar energy is another renewable and clean source of power that does not directly emit greenhouse gases. Thus, it is not a major source of greenhouse gas emissions.

Based on this information, option A: Deforestation is the correct answer as it releases significant amounts of carbon dioxide into the atmosphere, contributing to greenhouse gas emissions.

A major source of greenhouse gas emissions is A: Deforestation.