The Greenhouse Effect: Mechanism

What type of radiation reaches Earth from the Sun?

Mainly short-wave radiation, including visible light.

What happens when the Earth's surface absorbs solar radiation?

The surface warms up.

What type of radiation does the warmed Earth emit?

Long-wave infrared radiation.

What happens when greenhouse gases absorb infrared radiation?

They gain energy and emit infrared radiation in different directions.

How does the greenhouse effect warm the Earth's surface?

Greenhouse gases absorb and re-emit infrared radiation, reducing the rate of energy loss to space.

Why is the greenhouse effect not simply caused by trapping sunlight?

Greenhouse gases mainly affect outgoing infrared radiation from the Earth.

Does all solar radiation reach the Earth's surface?

No, some is reflected or absorbed by the atmosphere and clouds.

Does all infrared radiation escape directly into space?

No, some is absorbed by greenhouse gases.

Why does increasing carbon dioxide concentration increase warming?

It increases the atmosphere's absorption of outgoing infrared radiation.

Why does Earth eventually reach a new energy balance after greenhouse gas concentrations rise?

The planet warms until outgoing energy to space balances incoming solar energy.

What is the difference between the greenhouse effect and ozone depletion?

The greenhouse effect concerns infrared radiation and warming, while ozone depletion concerns increased ultraviolet radiation reaching Earth.

Why is the greenhouse effect necessary for life?

Without it, the Earth's average surface temperature would be much lower.