Myth: Water vapour is the main cause of global warming

The main greenhouse gas isn’t CO₂, it’s water vapour. It is responsible for about half of all global warming, yet there is no way we can exercise control over it. As such, there is nothing we can do about most of the warming that is taking place. 

Fact:

Water vapour is an important greenhouse gas, but its level is determined by atmospheric and sea surface temperatures. Studies show that for every 1°C of warming, there is a 7 percent increase in water vapour. This creates a powerful feedback effect that further heats the atmosphere and the oceans. In other words, we do have control over water vapour, but indirectly, via our emissions of CO₂. The only way to stop water vapour from increasing is to stop emitting CO₂ and other greenhouse gases.