What does radiative forcing measure?

• A. Radiative forcing describes the change in energy balance in the atmosphere due to a greenhouse gas; it's used to compare potency of gases.
• B. It measures soil moisture content.
• C. It is a monetary metric for climate finance.
• D. It refers to biodiversity indices.

Answer: (A)

Radiative forcing measures how much a perturbation to the climate system changes the balance between incoming solar energy and outgoing infrared radiation at the top of the atmosphere. It captures the net change in Earth’s energy budget caused by a greenhouse gas (and related factors) and is expressed in watts per square meter, which allows us to compare how strongly different gases influence warming or cooling. This framing—change in energy balance and a basis for comparing the potency of gases—is why the correct choice is best. Other options describe different concepts (soil moisture, a monetary metric for climate finance, or biodiversity indices) and do not pertain to the energy balance or the comparative measure radiative forcing provides.