if global warming adds somany feet of water to the oceans, how would the increase in the weight of the water affect tectonic movements? could the extra weight cause activity like volcanoes or earthquakes?

Well its true that global warming is very serious problem and we have to make efforts to make it less otherwise we have to face great problems, due to it. And this is sure that its extra weight will cause activity like volcanoes or earthquake.



Green Energy

Think about it this way...
If you have bathtub full of water (representing the ocean) With a bunch of ice cubes in it (representing the polar ice caps) would it weigh any different if the ice were still frozen or melted??

Same weight either way, it was there all along.

But on a flat surface, would a piece of ice spread faster than the fluid water? This is what causing the wobble of earth's rotation......sort of.