The earth's water storage is 1.36 billion cubic kilometers. But the available fresh water resources only account for 2.5% of its total water volume, and only a part of rivers, lakes and groundwater in this very few fresh water resources account for about 0.26% of the total water volume of the earth. How many cubic kilometers of fresh water can humans really use?
地球储水共13.6亿立方千米．但可利用的淡水资源仅占其总水量的2.5%，而在这极少的淡水资源中只有江河湖泊和地下水中的一部分，约占地球总水量的0.26%．人类能真正利用的淡水有多少立方千米？
<result>884_000</result>