There is growing concern about the rapidity and extent of climate change in recent decades in the Arctic. The changes already evident in the Arctic, such as the cyclonic shift in the distribution of Atlantic and Pacific water masses, atmospheric pressure and winds, as well as the thinning and retreat of the sea ice, will be felt first and most dramatically around the circum-Arctic shelves, which comprise nearly 50% of the area of the Arctic Ocean. In this context, the Laptev Sea and its Siberian hinterland are of particular interest because of their distance both from the Atlantic and Pacific Oceans. River discharge into the Laptev Sea constitutes a key source for the Arctic freshwater input, and it generates a shallow brackish layer on top of the halocline. The shallow Laptev Sea shelf is a major area of sea-ice production that links the Siberian shelves of the Arctic Ocean with the Nordic seas. During the Last Glacial Maximum, most of these shelves were above sea level and developed thick permafrost sequences; today they are submarine, after having experienced the postglacial late Pleistocene and Holocene transgression. The history of the submarine permafrost and its modern state of decay are largely unknown. © 2007 The Geological Society of America. All rights reserved.