It takes a lot of energy to turn water into vapour. When water vapour condenses to form clouds, this stored energy is released, warming the surrounding air and making it rise and cool, leading to more water condensing out, and so on. This process provides the energy that fuels much extreme weather, such as thunderstorms. It is why tropical cyclones, or hurricanes, form only over warm seas: without a plentiful supply of moist air, they soon run out of energy.
As the lower atmosphere gets warmer and wetter over the coming decades, there will be more fuel available to power extreme storms. But how often will this fuel ignite? Hurricanes are relatively rare because they form only when conditions are just right. While higher sea-surface temperatures will favour their formation, stronger high-level winds may rip them apart. The result could be fewer hurricanes overall, but with greater strength when they do occur. As the destructive power of hurricanes rises exponentially with increasing wind speed, a few intense storms could wreak more havoc than many weak ones.
At temperate northern latitudes, the news might be better. There winter storms are powered largely by the temperature differences between cold air from the poles and warmer air masses from the tropics. Such storms may become less common as rapid warming in the Arctic reduces the temperature differences.