Canada Is Still Rising Out of the Sea

Along the shore of Hudson Bay, in northern Canada, line after line of pale ridges runs for kilometers inland. Every one of them was once a beach. Since the last Ice Age the oceans have risen about 130 meters, so the sea didn't fall here: the land rose. And the land around Hudson Bay is still rising, by about a meter a century. What pushed it down, will the bay keep shrinking, and why is gravity weaker over Hudson Bay than it should be? Since 2002, satellites have watched that weak spot slowly fill in. Chapters 0:00 Ridges Far From the Sea 0:35 The Sea Didn't Fall 0:59 What Pushed the Land Down? 2:12 Is It Finished? 3:13 The Weak Spot in Earth's Gravity Sources Sella et al. 2007, "Observation of glacial isostatic adjustment in stable North America with GPS", Geophysical Research Letters: https://doi.org/10.1029/2006GL027081 Manitoba Geological Survey 2026, "Glaciomarine and marine sediments": https://gov.mb.ca/iem/geo/gis/sgcms/g... Parks Canada 2026, "Sloop Cove", Prince of Wales Fort: https://parks.canada.ca/lhn-nhs/mb/pr... Dyke & Prest 1987, "Late Wisconsinan and Holocene History of the Laurentide Ice Sheet", Géographie physique et Quaternaire: https://doi.org/10.7202/032681ar Simon et al. 2014, "A relative sea-level history for Arviat, Nunavut", Quaternary Research: https://doi.org/10.1016/j.yqres.2014.... Simon et al. 2016, "A glacial isostatic adjustment model for the… Laurentide Ice Sheet", Geophysical Journal International: https://doi.org/10.1093/gji/ggw103 Lambeck et al. 2014, "Sea level and global ice volumes from the Last Glacial Maximum…", PNAS: https://doi.org/10.1073/pnas.1411762111 Tamisiea et al. 2007, "GRACE Gravity Data Constrain Ancient Ice Geometries", Science: https://doi.org/10.1126/science.1137157 Simons & Hager 1997, "Localization of the gravity field and the signature of glacial rebound", Nature: https://doi.org/10.1038/37339 Dyke & Sladen 2010, "Permafrost and Peatland Evolution in the Northern Hudson Bay Lowland", Arctic: https://doi.org/10.14430/arctic3332 Packalen et al. 2014, "Carbon storage and potential methane production in the Hudson Bay Lowlands", Nature Communications: https://doi.org/10.1038/ncomms5078 Hansell et al. 1983, "Permafrost Development in the Intertidal Zone at Churchill", Arctic: https://doi.org/10.14430/arctic2263 Tsuji et al. 2009, "Post-Glacial Isostatic Adjustment and Global Warming in Subarctic Canada", Arctic: https://doi.org/10.14430/arctic176 IPCC 2021, "Summary for Policymakers", Climate Change 2021: The Physical Science Basis: https://doi.org/10.1017/9781009157896... Piercey-Normore 2008, "A Survey of Lichens and Bryophytes… on a Calcareous Beach Ridge", The Canadian Field-Naturalist: https://doi.org/10.22621/cfn.v122i3.599 UT Center for Space Research 2026, "GRACE and GRACE-FO": https://www2.csr.utexas.edu/grace/ Mass change on screen: our own calculation from the CSR GRACE/GRACE-FO RL06.3 mascons (H. Save, 2024), UT Center for Space Research: https://www2.csr.utexas.edu/grace/RL0... Imagery and data Shapes are drawn on present-day imagery; diagrams are not to scale. Contains modified Copernicus Sentinel data 2024. Terrain: produced using Copernicus WorldDEM-30 © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved. The organisations in charge of the Copernicus programme by law or by delegation do not incur any liability for any use of the Copernicus WorldDEM-30. NASA Blue Marble Next Generation (NASA Earth Observatory); map data: Natural Earth. Ice outlines simplified and recolored from NADI-1, CC BY 4.0. Dalton et al. 2023, Quaternary Science Reviews: https://doi.org/10.1016/j.quascirev.2... NADI-1 data, Dalton et al. 2023, Zenodo: https://doi.org/10.5281/zenodo.8161764 GPS velocities: MIDAS, Nevada Geodetic Laboratory. Blewitt, Hammond & Kreemer 2018, "Harnessing the GPS data explosion for interdisciplinary science", Eos: https://doi.org/10.1029/2018EO104623 Gravity: GOCO06s via ICGEM, CC BY 4.0; changes made: shown as gravity anomalies, broad pattern only (degrees 2-48). Kvas et al. 2019, "The satellite-only gravity field model GOCO06s", GFZ Data Services: https://doi.org/10.5880/ICGEM.2019.002 Sea-level curve at Arviat after Simon et al. 2014; the James Bay shoreline steps are a schematic after the models in Tsuji et al. 2009. Music by John Bartmann (Wikimedia Commons, CC0) and Umplix (OpenGameArt, CC0). Type: Open Sans (SIL OFL 1.1). Voice: Kokoro (Apache-2.0), synthesized. Illustrations drawn as code by us; no stock, no AI images. Corrections policy: if we got something wrong, we fix this description and pin a comment saying what changed and when. Found an error? Say so in the comments with a source, and we will check it. Borders note: maps use Natural Earth's default boundaries and are not a statement on any disputed boundary. #hudsonbay #geography #iceage #geology