Rapid water level rise drives unprecedented coastal habitat loss along the Great Lakes of North America

Lake Michigan rose to record high water levels in the 2010s; during this time, some coastal sites experienced habitat loss rates an order of magnitude higher than during previous high water periods throughout the 20th century. The high magnitude and rapid rate of rise observed during the 2012–2020 period in combination with a slight increase in the percentage of storm waves likely accelerated habitat loss rates beyond levels that were observed over the past century. Our data suggest that rapid and relatively large changes from low water levels to high water levels are the main driver of large erosional losses, as the coastal system shifts abruptly from one water-level regime to another. One likely impact of climate change on Great Lakes’ water level is an increase in the variability of fluctuations, thus more scenarios of abrupt and rapid water-level rise and associated habitat loss are expected in the future. We propose that the unprecedented habitat loss observed during the 2012–2020 timeframe will become the new normal in the coming century as enhanced variability in water levels facilitates sustained coastal land loss.