envr 1000 - unit 4, atmosphere and climate change, pt 3

Melting ice and sea levels

Global warming is causing rapid melting of continental and polar ice leading to rising sea levels

Arctic sea ice decline

In 2015 Arctic sea ice covered about half the area it covered in 1979

Antarctic ice retreat

The Antarctic ice pack has been shrinking due to warming temperatures

Human-caused climate change

Increase in atmospheric carbon dioxide from burning fossil fuels is the main driver

Arctic amplification

Faster warming in the Arctic compared to the rest of the world

Feedback loop

A cyclic process where a system’s output becomes input for the same system

Positive feedback loop

Process that amplifies change and pushes the system toward greater extremes

Climate feedback example

Loss of sea ice exposes darker ocean surfaces which absorb more sunlight and increase warming

Albedo effect

Darker surfaces absorb more solar energy while lighter surfaces reflect it

Sea ice feedback

Less ice lowers albedo leading to more heat absorption and further melting

Greenhouse effect

Earth absorbs solar radiation and re-emits infrared radiation that is trapped by greenhouse gases

Greenhouse gases

Atmospheric gases that absorb infrared radiation and warm the planet

Examples of greenhouse gases

Water vapor, carbon dioxide, methane