Here's why:

* Albedo is a measure of how much light a surface reflects. A high albedo means a surface reflects a lot of light.

* Clouds are made up of water droplets or ice crystals, which are very reflective.

* Sunlight is composed of many wavelengths of light, including visible light and infrared radiation.

* Clouds reflect a significant portion of the sunlight that reaches them, preventing it from reaching the Earth's surface.

This reflection of sunlight has important implications for the Earth's climate:

* Cooling effect: By reflecting sunlight, clouds contribute to a cooling effect on the Earth's surface.

* Regulation of Earth's temperature: Clouds help regulate the Earth's overall temperature by reflecting a portion of incoming solar radiation.

It's important to note that while clouds with a high albedo tend to cool the Earth, other factors like cloud type, thickness, and altitude can influence their overall effect on climate.