Which one of the following is responsible for the negative forcing or cooling of the atmosphere?

Stratospheric ozone changes are linked to a negative radiative forcing that cools the atmosphere.

Water vapour is a strong greenhouse gas producing positive, warming forcing.

Tropospheric ozone near the surface acts as a warming greenhouse gas.

Black carbon absorbs sunlight and warms the atmosphere, a positive forcing.

Depletion of stratospheric ozone has contributed a small cooling effect overall.

Radiative forcing measures how a factor pushes climate towards warming or cooling.