How might climate change alter the hydrological cycle in drainage basins?

• A. Changes in precipitation patterns, intensity, and ET can lead to more extreme floods/droughts and shifts in baseflow.
• B. Climate change will eliminate all droughts in most basins.
• C. Precipitation patterns remain unchanged; only temperature increases.
• D. Evaporation rates will always decrease.

Answer: (C)

The main idea here is that climate change reshapes how water moves through a drainage basin, not just how warm it gets. Warmer conditions don’t just add heat; they alter when and how precipitation falls, how much moisture is lost to the atmosphere, and how water is stored and released from soils, rivers, and groundwater. Because the atmosphere can hold more moisture, rainfall patterns can shift, with some regions receiving more rainfall and others less, and rainfall events becoming more intense. This changes runoff generation and recharge, affecting baseflow in streams and rivers. Evapotranspiration tends to rise with higher temperatures when moisture is available, which can reduce soil moisture and alter river flows, while heavy rains can increase groundwater recharge and modify baseflow timing. Snowmelt timing can also change, reshaping seasonal runoff. Taken together, climate change can lead to more extreme floods and droughts and shifts in baseflow, rather than a simple, uniform change limited to temperature.

Statements that precipitation stays unchanged or that droughts will disappear or that evaporation always decreases don’t reflect how the hydrological cycle responds to warming, where multiple components interact and extremes often intensify.