The graph shows how the amount of water used worldwide changed between 1900 and 2000.

Throughout the century, the largest quantity of water was used for agricultural purposes, and this increased dramatically from about 500 km3 to around 3000 km3 in the year 2000. Water used in the industrial and domestic sectors also increased, but consumption was minimal until mid-century. From 1950 onwards, industrial use grew steadily to just over 1000 km3, while domestic use rose more slowly to only 300 km3, both far below the levels of consumption by agriculture.

The table illustrates the differences in agricultural consumption in some areas of the world by contrasting the amount of irrigated land in Brazil (26,500 km2) with that in the D.R.C. (100 km2). This means that a huge amount of water is used in agriculture in Brazil, and this is reflected in the figures for water consumption per person: 359 m3 compared with only 8 m3 in the Congo. With a population of 176 million, the figures for Brazil indicate how high agricultural water consumption can be in some countries.