Venus and Greenhouse Effect?

Question

What started the greenhouse effect on Venus? Why is it so big on Venus but not on Earth?

Answer 1

There are several factors that contribute to the runaway greenhouse on Venus, From the web: Venus is covered with an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light; this was a subject of great speculation until some of its secrets were revealed by planetary science in the twentieth century. Venus has the densest atmosphere of all the terrestrial planets, consisting mostly of carbon dioxide, as it has no carbon cycle to lock carbon back into rocks and surface features, nor organic life to absorb it in biomass. It has become so hot that the earth-like oceans that the young Venus is believed to have possessed have totally evaporated, leaving a dusty dry desertscape with many slab-like rocks. The best hypothesis is that the evaporated water vapor has dissociated, and with the lack of a planetary magnetic field, the hydrogen has been swept into interplanetary space by the solar wind. The atmospheric pressure at the planet's surface is 92 times that of the Earth.

Answer 2

According to the information I've received from watching the shows about the universe (including Venus) on the History channel----Venus is now suffering with a runaway greenhouse effect and what started it, or at least made it continue, is the cloud strada on Venus itself.  Thank goodness the Earth hasn't suffered with the runaway greenhouse effect, however, research is now proceeding as to the problems involved.  One thing, however, our cloud cover on Earth isn't as dense and the clouds on Venus, yet!