(I'm not saying global warming isn't a thing!)
So, any fool will tell you that cloudy days are colder days, some times significantly so. When there are multiple cloudy days the temperature will plummet.
So if The oceans evaporate due to heat, clouds will form. If clouds form, more sunlight gets reflected into space. When sunlight is reflected, everyone wins (or at least doesn't cook).
So, what am I missing here? If it's not obvious, my understanding of climatology is limited to the news and a 5th grade understanding of the water cycle, so simple explanations would be preferable if possible.