Survival skills
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
Global public good
Although not the only example, no better example can be found than the issue of potable water. Water has always been an important and life-sustaining drink to humans and is essential to the survival of all known organisms. Over large parts of the world, humans have inadequate access to potable water and use sources contaminated with disease vectors, pathogens or unacceptable levels of toxins or suspended solids. Drinking or using such water in food preparation leads to widespread waterborne diseases, causing acute and chronic illnesses or death and misery in many countries. While the global water cycle is the subject of advanced scientific study and observation, it is still an incompletely understood process. If availability of water for human consumption is left solely to market forces, those who are most in need of water for subsistence-level survival are also those least likely to be able to purchase it at a market price. Since the water cycle and the natural flows of fresh water resources do not obey the limits of political boundaries, neither can these water resources be managed solely by local- or national-level public authorities. Privatization of such resources can be used as a method of avoiding contentious public policy-making processes, but is likely to produce inequities. The history of the development of water supply and sanitation in Ecuador and resulting water conflicts there are an example. Thoughtful design of transnational or international water management authorities over such global common-pool resources will play a large part in possible solutions to peak water problems.