What is a consequence of glacier retreat for freshwater availability in river basins?

• A. Increases long-term freshwater availability
• B. Increases salinity of rivers
• C. Decreases short-term rainfall
• D. Reduces long-term freshwater availability in many basins

Answer: (D)

Glaciers act as natural freshwater reservoirs for many river basins, slowly releasing meltwater that sustains river flow during dry periods. When climate warms and glaciers retreat, their stored water becomes smaller, so the long-term supply of freshwater to those basins decreases. In the near term, melt can briefly boost river flows, but as glaciers lose mass over decades, the sustained discharge declines, leading to reduced long-term water availability in many basins. This isn’t mainly about rainfall changes or river salinity; glacier retreat changes how much water is available in rivers over the long term.