Abstract

The hydrological balance in mountainous regions is being altered by climate change. In central Chile, rising temperatures and decreasing precipitation accelerate glacier retreat, initially increasing runoff. However, once the maximum (peak water) is surpassed, water availability decreases to levels below those prior to climate change. This study assesses the water balance for the 21st century in the Maipo River basin, Chile (33 degrees S). Results obtained from simulations with an Integrated Assessment Model are disaggregated for two climate scenarios: high (SSP5-8.5) and low (SSP1-2.6) greenhouse gas (GHG) emissions. The findings indicate that the basin has already surpassed peak water and will face increased water stress. In the high-emission scenario, it could reach Day Zero, where demand exceeds water availability, highlighting the urgency of sustainable water management strategies.