Venus has an atmosphere 90 times more massive than Earth's with over 90% carbon dioxide, resulting in a surface temperature of 477°C, 523°C higher than it would be without a greenhouse effect. Earth has a surface temperature of 15°C, made warmer by 33°C from its atmosphere containing around 1% water vapor and 0.04% carbon dioxide. Mars, with an atmosphere less than 1% of Earth's mass and over 80% carbon dioxide, has a surface temperature of -47°C, only 10°C warmer than without its thin greenhouse effect.

9. Other planets also have Greenhouse Effects,
but these are unsuitable for life
Atmosphere: mass 90x
Sun Venus earth’s
GH Gases: >90% CO2
Sfc. Temp.: 477°C
GH Effect: 523°C
FAR TOO HOT!
GH Gases: ~0.04% CO2
Earth ~ 1% H2O
Sfc. Temp.: 15°C
GH Effect: 33°C
NOT BAD!
Atmosphere: mass <1% earth’s
Mars
GH Gases: >80% CO2
Sfc. Temp.: -47°C
GH Effect: 10°C
FAR TOO COLD!

10. 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 ~33°C warmer than it
would be without an atmosphere
Greenhouse gases are transparent to shortwave
but absorb longwave radiation
– Thus the atmosphere stores energy

11. Electromagnetic Spectrum
incoming outgoing