Global Warming - Venus

Discuss how the atmosphere of Venus can be used to illustrate the danger of extreme global warming.

Venus has an atmosphere that is 90 times that of Earth's. Consequently surface temperatures are considerably higher, hot enough to melt lead. Its dense carbon dioxide atmosphere acts as a greenhouse gas to keep temperatures high. The average surface temperature on Venus is 462°C compared to 14°C on Earth.

Understanding the conditions that led to Venus having such an atmosphere are important to some astronomers.

There are several reasons for this and can be discussed.

  • Venus is 1/3 nearer the Sun than the Earth. This is a good reason why it is hotter.
  • Very slow rotation spin
  • Venus lacks a carbon cycle so that carbon is stored in the oceans , rocks and life.
  • Lack of plate tectonics to vent internal heat.
  • Radar mapping has detected large number of volcanoes (no evidence that these are active)
  • Some have proposed that Venus once had a water surface but this was boiled up.
  • Lack of a magnetic field allowed some atmospheric elements such as hydrogen to evaporate into space.



What conditions may have existed on Venus to create its atmosphere?

Earth-Venus Comparisons
  Earth Venus
AU from Sun 1 AU 0.72 AU
Km from Sun 149,600,000 km 108,000,000 km
Diameter 12,750 km 12,100 km
Rotation (Day) 23h,56m,4s 243 days
Orbit (Year) 365.25 days 224 days
No. of Moons 1 0
Tilt of Axis 23.5° 177°
Gravity Earth =1) 1 0.9