It was probably started by volcanic gasses (some of which are greenhouse gasses) but the continued avalanche of heating was caused by the fact that water is the most dangerous greenhouse gas. Once enough water is in the upper atmosphere, the greenhouse effect will bring more water to the upper atmosphere, adding to the greenhouse effect and evaporating more water from the oceans. This eventuality turns the oceans into deserts - whether on Venus or on Earth.
Efforts are underway to prevent greenhouse gases from entering the atmosphere and also to profitably remove them from the air to make new products and storage places, like storing the gasses in rocks.
I suggest that we limit the concentration of water in the atmosphere by getting our drinking water from the air. This would be a good use of solar energy, wind energy, and wave energy. It would also reduce the amount of rain and snow falling from the sky and reduce the incidence of all sorts of storms.
The theory behind this idea is very simple. We now get all of our fresh water from the sky. The sun evaporates water from all wet places on Earth. This forms clouds. On days where the air is at 100% of saturation, it rains or snows. That is the source of the water that we pipe into our homes. By utilizing environmental energy to extract water from the air at lower percentages of saturation, we get the water before it rains or snows. Along with this benefit, we prevent runaway global warming by reducing the greenhouse effect of water vapor in the upper atmosphere.
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