Explain “Cloud feedback” and “Lapse-rate feedback”.

Cloud feedback and lapse-rate feedback are two important mechanisms that contribute to the amplification or dampening of climate change, particularly in response to increases in greenhouse gas concentrations.

Cloud feedback refers to the role of clouds in amplifying or mitigating changes in the Earth's climate. Clouds can either reflect incoming solar radiation back into space, leading to a cooling effect, or trap outgoing infrared radiation emitted by the Earth's surface, enhancing the greenhouse effect and resulting in a warming effect. The net effect of clouds on climate depends on their type, altitude, and spatial distribution. For example, low, thick clouds tend to have a cooling effect by reflecting sunlight, while high, thin clouds may have a warming effect by trapping heat.

Lapse-rate feedback is related to the change in temperature with altitude in the atmosphere. As the atmosphere warms due to increasing greenhouse gas concentrations, the temperature profile, or lapse rate, can change. Generally, the rate at which temperature decreases with altitude (adiabatic lapse rate) decreases with warming. This can lead to a positive feedback, as a reduced lapse rate enhances the greenhouse effect, amplifying warming. Conversely, if the lapse rate increases with warming, it can act as a negative feedback, dampening the warming effect.

Both cloud feedback and lapse-rate feedback are critical components of climate sensitivity, which quantifies how much the Earth's surface temperature will change in response to a given increase in greenhouse gas concentrations. Understanding these feedback mechanisms is essential for predicting future climate change and informing climate mitigation and adaptation strategies.