will have doubled worldwide and over half of the world’s cere- als will be used to feed livestock, compared to one-third today. Indeed, this cereal alone could have fed the entire projected population growth. Instead, unless changes are made, our wa- ter consumption to grow irrigated cereals for animal feed will have to increase by at least 30–50%, if not more, simply to sup- port heavily fertiliser-based production schemes. In some re- gions, as in Pakistan, water demand will increase by 50–70% by 2050, while availability will decline at the same time.

Irrigated croplands, mainly rice, in the watersheds of major Asian rivers are all to some extent depending on runoff from the high mountain regions in addition to monsoon rains which also recharge groundwater reservoirs. Given the high level of uncertainty regarding future runoff levels, and also the highly variable contribution of glacial water and snow- melt from the mountains, future agricultural production also faces significant uncertainty. For rivers like the Indus, Syr Darya, and Amu Darya, a major decline in the water flow will have devastating impacts on food production and domestic availability, as there are few, if any, alternatives to this water.

for cereals for production of animal feed and for human con- sumption will increase water demand by an additional 30– 50% within a few decades; and perhaps by 70–80% by 2050. Thirdly, climate change may not only disrupt monsoon pat- terns, it may also significantly alter the main flow and season- ality of many of the large Asian rivers within a few decades, with disastrous impacts on food production as a result (Nel- lemann and Kaltenborn, 2009).

The demand for food and irrigation water will continue to in- crease towards 2050 as a result of population growth of an additional one billion people in Asia, increased incomes, and growing consumption of meat. In Pakistan, for example, one of the countries with the highest water scarcity and extreme dependency on the Indus River, the population is projected to increase by 82% from around 184 million in 2010 to around 335 million by 2050. By then, meat consumption per capita

The irrigated cropland in the basins of those Asian rivers that are most dependent upon the mountains for water flow, comprises approximately 857,830,000 ha. The average pro- duction of irrigated rice is projected at 6 tonnes/ha (range 2–10 tonnes/ha), compared to 2–3 tonnes/ha for non-irrigat- ed land (average of both combined, about 3.3 tonnes/ha in Asia). Water from the Hindu Kush-Himalayas and the central Asian mountain region thus supports the production of over 500 million tonnes of cereals per year, equivalent to nearly 55% of Asia’s cereal production and 25% of the world pro- duction today. By 2050, as projected by FAO, global cereal production needs to be around 3000 million tonnes in order to meet demand. However, some estimates suggest that due to environmental degradation in the watersheds, floods, and reduced water flow due to climate change in the Hindu Kush- Himalayas, cereal production in Asia could become 10% to 30% lower than projected demand, corresponding to a 1.7–5% global reduction in cereal production (Nellemann and Kalten- born, 2009; UNEP, 2009). While we do not at this stage have any good projections, the numbers do reveal how important irrigation water and flood control is in the Hindu Kush- Himalayas region for global food security (UNEP, 2009).

41