Question

question 21
4 pts
which of the following is correct about carbon footprint?

• the concentration of co2 in the atmosphere has seasonal variations, reaching its peak during mid fall
• carbon footprint is unrelated to energy consumption
• carbon footprint is usually reported in terms of tons of co2 - equivalent
• carbon footprint only includes emissions of carbon dioxide (co2)
• in the u.s., all firms are required to report their carbon footprint because of regulation (e.g, cap and trade)

Explanation:

• Analyze each option:
• Option 1: CO₂ concentration peaks in winter (not mid - fall) due to less photosynthesis, so this is wrong.
• Option 2: Energy consumption (like burning fossil fuels) is a major source of carbon emissions, so carbon footprint is related to energy consumption. This is wrong.
• Option 3: Carbon footprint is commonly reported in tons of CO₂ - equivalent (to account for other greenhouse gases with CO₂ - equivalent warming potential). This is correct.
• Option 4: Carbon footprint includes emissions of other greenhouse gases (e.g., methane, nitrous oxide) in addition to CO₂, converted to CO₂ - equivalent. So this is wrong.
• Option 5: In the U.S., not all firms are required to report carbon footprint; reporting requirements vary. So this is wrong.

Answer:

C. Carbon footprint is usually reported in terms of tons of CO₂ - equivalent