Humanity uses a little less than half the water available worldwide. Yet occurrences of shortages and droughts are causing famine in some areas, but industrial and agricultural by-products are polluting water supplies. 【S1】 1 Since the world's population is expecting to double in the next 50 years, 【S2】 2 many experts think we are on the edge of a widespread water crisis. But that doesn't have to be the outcome. Water shortages do not have to trouble the world—if we started valuing water more than we 【S3】 3 have in the past. Just like we began to appreciate petroleum more after 【S4】 4 the 1970s oil crisis, today we must start looking at water from a fresh economical perspective. We can no longer afford to consider water a 【S5】 5 virtual free resource of which we can use as much as we like. 【S6】 6 Instead, for all uses except the domestic demand of the poor, governments should price water to reflect their actual value. This means 【S7】 7 charging a fee for the water itself as well as for the demand costs. 【S8】 8 Governments should also protect this resource by providing water with more economically and environmentally sound ways. 【S9】 9 Often the cheapest way to provide irrigation water in the dry tropics is through small-scaled projects, such as gathering rainfall in depressions 【S10】 10 and pumping it to nearby cropland. 【S1】