Which sector is the largest source of global greenhouse gas emissions?
Explanation: The correct answer is D) Energy. The energy sector, including electricity generation, heat production, and fuel combustion, is the largest source of global greenhouse gas emissions. This is primarily due to the burning of fossil fuels, such as coal, oil, and natural gas, which release carbon dioxide (CO2) into the atmosphere.
Which of the following activities is a significant source of methane emissions?
Explanation: The correct answer is C) Livestock farming. Livestock farming, particularly the digestion process in ruminant animals like cows and sheep, is a significant source of methane (CH4) emissions. Methane is released during the microbial breakdown of organic matter in the animals' digestive systems, and it is a potent greenhouse gas with a higher warming potential than carbon dioxide.
Which greenhouse gas is primarily associated with land-use changes, such as deforestation and forest degradation?
Explanation: The correct answer is B) Carbon dioxide (CO2). Land-use changes, such as deforestation and forest degradation, are primarily associated with carbon dioxide (CO2) emissions. When trees are cut down or burned, the carbon stored in the vegetation and soil is released into the atmosphere as CO2. Deforestation contributes significantly to global greenhouse gas emissions and reduces the capacity of forests to absorb CO2 through photosynthesis.
Which sector is a major source of nitrous oxide emissions?
Explanation: The correct answer is D) Agricultural activities. Agricultural activities, such as the use of synthetic fertilizers, livestock manure management, and the cultivation of certain crops, are a major source of nitrous oxide (N2O) emissions. Nitrous oxide is released during microbial processes in agricultural soils and from nitrogen-based fertilizers, contributing to both climate change and stratospheric ozone depletion.
Which sector is a significant source of fluorinated gases?
Explanation: The correct answer is B) Semiconductor manufacturing. The semiconductor manufacturing industry is a significant source of fluorinated gases (F-gases), such as hydrofluorocarbons (HFCs) and sulfur hexafluoride (SF6). These gases are commonly used in various industrial processes and as refrigerants or insulating materials. F-gases have a high global warming potential and can persist in the atmosphere for a long time, contributing to climate change.