P2U2 03Feedback Loops in the Global Energy Balance

Front

What is Earth's global energy balance?

Back

Earth's energy balance is the equilibrium between incoming solar radiation and outgoing terrestrial radiation over a one-year period. If this balance is disrupted, the global average temperature of Earth will change.

Front

What is a feedback mechanism in the context of climate change?

Back

A feedback mechanism is a process within a system where a change can be either accelerated or slowed down and stabilized. In climate change, feedback loops can be positive or negative.

Front

What is positive feedback in climate change?

Back

Positive feedback increases change and accelerates the rate of change. An example is the release of methane gas due to the thawing of permafrost, which traps more heat and accelerates further thawing.

Front

What is negative feedback in climate change?

Back

Negative feedback reduces change and slows down the rate of change. An example is increased evaporation and cloud formation from rising sea and atmospheric temperatures, which can block incoming solar radiation and result in cooler temperatures.

Front

What is albedo?

Back

Albedo is the reflectivity of a surface. Different surfaces have varying albedo values, with fresh snow having a high albedo and dark forests having a low albedo.

Front

How do changes in terrestrial albedo act as feedback loops?

Back

Changes in terrestrial albedo, particularly in the Arctic, can act as positive feedback loops. Melting snow and ice expose darker surfaces with lower albedo, leading to increased warming and further melting.