Research Publications

Freshwater systems are undergoing unprecedented pressures from climate-induced changes in seasonal patterns and intensification of hydrological extremes. The Laurentian Great Lakes Basin (GLB), which holds one-fifth of Earth's fresh surface water, is increasingly vulnerable to climate-induced hydrological changes with major implications for regional water management and agriculture. While previous studies have advanced the understanding of recent and projected hydrological changes in portions of the GLB, a comprehensive basin-wide evaluation of the GLB's hydrological responses under diverse climate change scenarios is lacking. Here, we present the first GLB basin-wide hydrological changes attributed to climatic drivers by comparing projected conditions (2025–2100) against recent historical baseline (1980–2014). We employ multi-model climate and hydrologic simulations combined with hydrodynamic modeling to project long-term changes in streamflow, lake levels, and surface water availability under three climate scenarios (SSP1-2.6, SSP3-7.0, SSP5-8.5). Results indicate a consistent basin-average warming trend of 3–8 °C by 2100, accompanied by seasonal redistribution of precipitation with concentrated amounts in winter and spring, and declines during summer. These changes drive substantial reductions in soil moisture (up to 12%) during critical crop growth periods, while spring flows peak earlier by up to 40 days. Although streamflow drought occurrence generally decreases across the basin, northeastern regions exhibit increased drought frequency due to intensified precipitation. Surface water storage will likely increase by ~20%, especially in the central GLB. Lastly, sustained rise in lake water levels are projected, with a likelihood of reaching a new record high in the near to mid-future, with ensemble spread indicating growing uncertainty toward the end of the century. These findings underscore the need for adaptive water strategies to mitigate hydrological risks and enhance agricultural resilience in the GLB under climate change.