| Water vapor source | Our estimates (km3/yr) | Earlier estimates (km3/yr) | References | |
| Major terrestrial biomes | ||||
| Croplands | 6800 | 2285 - 5500 | Postel et al. (1996), Shiklomanov (1996), Postel (1998) | |
| Temperate and tropical grasslands | 15,100 | 5800 | Postel et al. (1996) | |
| Temperate and tropical forests, woodlands, and taiga | 40,000 | 6800 | Postel et al. (1996) | |
| Bogs, fens, swamps, and marshes | 1400 | |||
| Subtotal | 63,200 | 14,885 - 18,100 | ||
| Other systems | ||||
| Green areas in urban settlements | 100 | 100 | Postel et al. (1996) | |
| Upstream rural water use | 210 | |||
| Lake evaporation | 600 | 600 | L´vovich (1979) | |
| Evaporation from large reservoirs (>100 x 106 m3) | 130 | 130 | L´vovich and White (1990) | |
| Evaporation from small reservoirs (<100 x 106 m3) | 30 | |||
| Tundra and deserts | 5700 | |||
| Subtotal | 6800 | 830 | ||
| Total | 70,000 | 15,715 - 18,930 | ||