This sounds a lot like "post glacial rebound". Basically during an ice age, the sheer weight of the ice / glaciers which form on the land push down on the tectonic plates beneath them. Since the Earth's crust is acutally floating on the molten core, it gets pushed down - a bit like what happens when you put a weight into a boat, causing sea levels to rise relative to the land because the land is pushed downwards. When the ice melts and the weight is removed, the crust starts to rise back up. This process takes tens of thousands, if not millions of years. Parts of Great Britain are still rising back up due to this effect at a rate of several centimeters per century, rebounding from the last ice age. There are 'raised beaches' several meters above modern-day sea levels in the UK, and in Scandanavia, which can be attributed to this effect. It seems suprising to me that modern - day climate scientists were not aware of this effect, since I was told about it in the late 80s by a member of the Environmental Science department of Bradforfd University.