Which of the following greenhouse gases (GHGs) has the longest lifetime in the atmosphere?

Which of the following greenhouse gases (GHGs) has the longest lifetime in the atmosphere?
A . Methane
B . Carbon dioxide
C . Fluorinated gas

Answer: C

Explanation:

Among the greenhouse gases (GHGs) listed, fluorinated gases have the longest atmospheric lifetimes. Here’s a detailed breakdown:

Methane (CH4):

Methane is a potent greenhouse gas with a significant impact on global warming. However, its atmospheric lifetime is relatively short, approximately 12 years.

Carbon Dioxide (CO2):

Carbon dioxide is the most prevalent greenhouse gas emitted by human activities, particularly from the burning of fossil fuels. CO2 can remain in the atmosphere for hundreds to thousands of years, but it is still not the longest-lived compared to fluorinated gases.

Fluorinated Gases:

Fluorinated gases, such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), are synthetic gases that have extremely long atmospheric lifetimes, often ranging from a few years to thousands of years. For instance, SF6 can remain in the atmosphere for up to 3,200 years.

These gases are typically used in industrial applications and have a high global warming potential (GWP) due to their longevity and heat-trapping capabilities.

CFA ESG Investing

Reference: The CFA Institute’s ESG curriculum emphasizes understanding the different types of greenhouse gases, their sources, and their impacts on climate change. The curriculum specifically points out the longevity and high global warming potential of fluorinated gases, which makes them a critical focus in ESG assessments and climate risk evaluations.