Mars Atmosphere: mass 80% CO 2 Sfc. Temp.: -47 C GH Effect: 10 C FAR TOO COLD! Other planets also have Greenhouse.

MarsAtmosphere: mass <1% earth’sGH Gases: >80% CO2

Sfc. Temp.: -47C GH Effect: 10C

FAR TOO COLD!

Other planets also have Greenhouse Effects, but these are unsuitable for life

EarthGH Gases: ~0.04% CO2

~ 1% H2OSfc. Temp.: 15C GH Effect: 33C

NOT BAD!

VenusAtmosphere: mass 90x earth’sGH Gases: >90% CO2

Sfc. Temp.: 477C GH Effect: 523C FAR TOO HOT!

Sun

The “Greenhouse Effect”

• The Earth’s surface thus receives energy from two sources: the sun & the atmosphere – As a result the Earth’s surface is ~33C warmer than it

would be without an atmosphere

Greenhouse gases are transparent to shortwave but absorb longwave radiation – Thus the atmosphere stores energy

Electromagnetic Spectrum

incoming outgoing