本文探讨发达国家工业用水零增长出现的时间及其原因。发达国家的经验表明 :较高的环境保护要求是工业用水减少的宏观社会背景,产业结构升级则是工业用水实现零增长的直接原因。第二产业所占的 GDP比重和就业比重的开始降低是工业用水减少的前奏,第二产业比重的明显降低——其实质是高耗水的重化工行业规模的绝对萎缩——几乎是工业用水停止增长的充分条件。

It’s difficult to forecast industrial water demand in developing countries when the size of industry enlarges quickly and the structure of industry changes rapidly. It’s especially unbelievable that industrial water demand will double in every 10 years or so for every developing country, because developed countries have set examples that industrial water use (here it means fresh water withdraw) may decrease when industrial structure changed from labor-and-capital-intensive type to technology-and-knowledge-intensive type. In this paper we mainly discuss the time and reasons of the decrease of industrial water use in developed countries. Following are the conditions or influence factors for the decrease of industrial water use in developed countries. Firstly, the stricter regulations of environmental protection are the macro background. Secondly, industrial structural upgrade, especially the migration of heavy-chemical industries from developed countries to developing countries, is the essential driving force. Thirdly, the promotion of the efficiency of industrial water use is the technological guarantee. Fourthly, the crude oil price rising or the petroleum crisis was the inducing factor but not the necessary condition. Finally, in some countries water resources shortage is one of the main reasons why industrial water use decreased. (But in most developed countries the ratio of fresh water withdraw to total water resources is still very low). When industrial water use decreased in developed countries, the corresponding proportion of secondary industry in total GDP ranged from 30% to 45%, while employment proportion of secondary industry ranged from 28% to 38%. From these figures we can get some quantitative concepts of the condition of industrial water use decrease in developed countries, but the qualitative judgement of the constriction of heavy-chemical industries is more important.