Lesson C3 - The "white" cryosphere and its albedo

MAIN SUBJECTS

Natural sciences

DURATION

Preparation: 20min

Activity: 1h30

SUMMARY

The students debate the role played by sea ice in the Earth’s climate and carry out an experiment to understand the importance of the cryosphere as a surface with a high albedo. This lesson also provides an opportunity to discuss climate system feedbacks.

KEY IDEAS

Due to its white colour, the cryosphere reflects most incoming solar radiation. It therefore regulates the amount of energy absorbed by the Earth.
The capacity of a surface to reflect solar radiation is called albedo.
Without the cryosphere, the temperature of the Earth's surface would be higher.
As the cryosphere melts, the Earth’s overall albedo is decreasing, which leads to additional warming. The surface covered by ice is shrinking faster every year. This initiates a dangerous cycle, called a positive feedback.
In the climate-ocean-cryosphere system there are many feedback loops (both positive and negative) that are very hard to stop once set in motion.

INQUIRY METHOD

Experimentation and documentary analysis