Water covers some 75% of the earth’s surface, while land covers 25%, approximately. Yet the former accounts for less than 1% of world GDP, the latter 99% plus. Part of the reason for this imbalance is that there are more people located on land than water. But a more important explanation is that while land is privately owned, water is unowned (with the exception of a few small lakes and ponds), or governmentally owned (rivers, large lakes). This gives rise to the tragedy of the commons: wh...