First, an initial basin efficiency rate (BE0) is calculated on the basis of the share of each irrigation technology applied in each respective OECD country (see Figure 23). The first is the cost related to changing to the more efficient irrigation efficiency per hectare (IE cost). The second is the total irrigated area (Al) in hectares in 2050. The third component is the share of total irrigated area in 2050 equipped with the more efficient irrigation technology.