Similarly, countries can import fossil fuels, mineral ores, and resources from the biosphere like fish and timber; but they cannot import water, which is essentially local, on a large scale and on a prolonged – much less permanent – basis. Water is heavier than oil, making it very expensive to ship or transport across long distances even by pipeline (which would require large, energy-intensive pumps).
水和其他自然资源不同。毕竟，许多资源都能找到替代品，包括石油，但水不行。类似地，国家可以进口化石燃料、矿石和其他诸如鱼和木材等生物资源；但国家不能进口水，从根本上说，水是大规模、长时间（尽管远非持久）的立国之本。水重于油，这决定了船运或长途输送（即使使用管道进行，而这又需要大型能源密集型水泵）成本极其高昂。