What effect does warming from below have on the atmosphere?

• A. Decreases stability
• B. Increases stability
• C. No effect
• D. Only affects humidity

Answer: (A)

Warming from below reduces stability by making the lower part of the atmosphere warmer and more buoyant relative to the air above. When the surface heats, the near-surface air becomes less dense. If a parcel of air is lifted, it cools as it rises, but because it starts warmer than its surroundings, it remains buoyant and continues to rise. That buoyancy means the air can freely ascend, creating convection and cloud formation. Humidity can influence how vigorous the convection is, but the primary effect of warming from below is to decrease stability, not to leave it unchanged or to act only on moisture.