Isostatic Rebound

Isostatic rebound is the slow uplift of crust that was depressed under a former ice sheet and is now recovering as the mantle flows back, the central part of glacial isostatic adjustment (GIA). After the Last Glacial Maximum, regions such as Fennoscandia, Hudson Bay, and northern North America began rising, with present rates up to about 9 to 10 mm per year near the former ice centers, while the peripheral bulge subsides. GIA changes relative sea level independent of ocean volume, so it must be modeled and removed (using models like ICE-6G) before a tide-gauge or altimetry trend yields the true ocean signal.