Reply #20: Increased global temperatures means increased ocean surface evaporation.

[Xithras]

Without even getting into the interruption to the gulf stream (which, unlike global warming, is still an unproven and controversial idea in the scientific community), the simple act of evaporation will cause trouble.

Increased evaporation means increased cloud cover. Increased cloud cover means increased solar reflection. Increased solar reflection means that surface temps drop. Surface temperature reductions under cloud cover mean decreased agricultural output and increased snowfall.

Ice age.

The problem is that this is a slow process. It may take decades, or even a century, before global warming heats the ocean enough to begin appreciably increasing the rate of evaporation. Since the ocean is a big heat sink, when the increased cloud cover reduces the amount of sunlight hitting the ocean, it may take decades more for it to cool back off. In the meantime the planet will get very cold, and very snowy.

Once the oceans "normalize" again, the world won't automatically warm back up either. Snow is just as reflective of solar radiation as clouds are, and a few decades of snowfall will result in a world that reflects most of its energy back into space. Remember that the natural state of ANY planet is "frozen solid", that solar radiation is our only source of heat, and that the atmosphere actually collects little of it on its own. When the ground reflects the radiation back into space, it takes a LONG time for the planet to warm up again.