[jkqwzsoo]

The caption for the image in the article expands on the theory a bit.

The idea is that as the ice melts, less weight is on the poles, which causes them to rise up. It’s proposed that the overall effect is to make the Earth more round/spherical lowering its moment of inertia. This effect is, at least in this theory, seems to be stronger than the effect of moving water out to the equator. It wouldn’t surprise me if the water that’s moving around simply isn’t massive enough to cause an effect the size observed. Same with the oil that you propose.