3.4.1. Blue Virtual Water

Our results show that except for a few years, Pakistan has been losing domestic blue virtual water due to its trade in the agricultural commodities (Figure 5a). As Pakistan is a net exporter of blue virtual water, this result is not surprising for the country. The average annual losses during 1990–1999 were <sup>−</sup>248 Mm<sup>3</sup> and increased to <sup>−</sup>5956 Mm<sup>3</sup> during 2000–2016. The most substantial losses of blue water were recorded in 2011, with a historic high of <sup>−</sup>11890 Mm3. During that particular year, in addition to its traditional export, that is, rice, Pakistan also exported large quantities of wheat, which caused the blue water losses to surge. For comparison, the water loss was equivalent to 7% of the total irrigation water used in Pakistan during 2011. In other words, Pakistan's negative blue net virtual water import is exerting additional pressure on the country's dwindling water resources. There have also been some years when Pakistan saved domestic blue water due to its trade (Figure 5a). The positive contribution of net virtual water import towards Pakistan's domestic blue water saving during the 1990s was due to massive net imports of wheat and during the late 2000s due to sharp but occasional increase in net imports of cotton.

**Figure 5.** Evolution of (**a**) blue and (**b**) green water-saving for Pakistan and at global level (1990–2016). Source: Authors' calculations based on data from Reference [39] (trade volumes) and sources mentioned in the Methods section (VWC).At the global level, however, the average saving of green virtual water has been positive but small, that is, 307 Mm3/year (Figure 5b), mainly due to a relatively smaller difference between the green VWC of Pakistan and those of its import partners. The global saving of green virtual water has consistently been positive since 2010.

Pakistan's trade in the agricultural commodities has also contributed to sizable positive savings of blue virtual water at the global level (Figure 5a). This was due to Pakistan's higher blue water productivity in producing its imported commodities, especially those of wheat and cotton. The rate of global blue virtual water savings has been decreasing over the years, with 3896 Mm3/year blue VW global saving during 1990–1999, 1702 Mm3/year BVW global saving during 2000–2009 and 459 Mm3/year blue VW global saving during 2010–2016.
