Final answer:
The availability of clean, accessible fresh water is the most critical feature of the global water budget, as it is essential for drinking, agriculture, and other human needs. The global water crisis is exacerbated by pollution, overuse, and climate change.
Step-by-step explanation:
From a human viewpoint, the most critical feature of the global water budget is the availability of clean, accessible fresh water. Water is essential for life, yet less than one percent of the world's fresh water is available for human use. Not only is water necessary for drinking, but it also supports agriculture, which consumes about seventy percent of our global water usage.
The situation is increasingly dire with the water crisis, as water scarcity affects billions, compounded by issues such as overuse, water pollution, and the effects of climate change. Approaches to extending our water supply, such as dams, aqueducts, and proper sewage treatment, are crucial, but the problem persists with an escalating global population and uneven distribution of rainfall.