Storms, Floods, and Droughts
The source of the rain that filled your town reservoir, or flooded your nearby river, or never arrived to water your crops, is most likely the ocean. The ocean contains 96% of the free water on Earth, and it acts like a massive water pump. It is powered by heat evaporating water into water vapor. The atmosphere transports it far and wide, until it condenses into rain or snow and completes the cycle by falling directly back on the ocean or returning via land, rivers, and underground aquifers back to the sea.
Now, as global temperatures have been rising, there is strong evidence that the ocean water pump has been revving up.