prosperity and crop productivity, being irrigated agriculture the dominant user of
water, accounting for about 85 % of global water use and projected to double by
2050 (Molden 2007; Pfister et al. 2011). Irrigated area is expected to rise by a
factor of 1.9 by 2050, while climate change is amplifying water stress by changing
patterns of water availability in many parts of the world (Lobell et al. 2008).
Because of that, the importance of cost analysis of water in the agricultural sector
would increase.
The world’s agriculture, hydroelectric power, and water supplies depend on
different components of the hydrological cycle, including the natural replenishment of surface and groundwater resources (Kang et al. 2009). Fujihara et al.
(2008) pointed out that water scarcity will not occur if water demand does not
increase; however, if the irrigated area is expanded under present irrigation efficiency rates, water scarcity will occur. Moreover, water availability is under threat
from changing climate because of possible precipitation decrease in some regions
of the world. In light of the uncertainties of climate variability, water demand, and
socioeconomic environmental effects, it is urgent to take some measures to use the
limited water efficiently and develop some new water resources (Kang et al. 2009).
The challenges of water scarcity are heightened by the increasing costs of
developing new water sources, land degradation in irrigated areas, groundwater
depletion, water pollution, and ecosystem degradation (Hanjra and Qureshi 2010).
Rosegrant and Cai (2002) estimated that under their baseline scenario, total
global water withdrawals for agricultural, domestic, and industrial use will
increase by 23 % from 1995 to 2025. The availability of sufficient water resources
is one of the major crises with overarching implications for many other world
problems especially poverty, hunger, ecosystem degradation, desertification, climate change, and even world peace and security (Khan and Hanjra 2009).
In China, where more than 300 cities already are short of water, these shortages
are intensifying (Khan et al. 2009). Water resources, critical for irrigation, are
under great stress as populous cities, states, and countries require and withdraw
more water from rivers, lakes, and aquifers every year (Hanjra and Qureshi 2010).
Recent flooding and heavy precipitation events worldwide have caused great
damage to crop production (Rosenzweig 2007). If the frequency of these weather
extremes were to increase in the near future, the cost of crop losses in the coming
decades could rise dramatically. On the other hand, The Fourth assessment report
(AR4) from the IPCC projected that drought-affected areas are likely to increase in
extent in the future, with Europe, the Mediterranean, and southern areas of
Australia at particularly high risk in the summer months (Gosling et al. 2011).
Moreover, significant increases in drought have also been projected for West
Africa, Central Asia, Central America, western Australia, the Middle-East, Indochina, and mid-latitude North American regions (Hirabayashi et al. 2008; Sheffield
and Wood 2008; Sillmann and Roeckner 2008).
In the twenty-first century, global agriculture has met the new challenge,
namely to increase food production for the growing population under increasing
scarce water resources, which can be achieved by improving crop water productivity (Kijne et al. 2003).
1 Strategies for Sustainable Plant Food Production
23
water, accounting for about 85 % of global water use and projected to double by
2050 (Molden 2007; Pfister et al. 2011). Irrigated area is expected to rise by a
factor of 1.9 by 2050, while climate change is amplifying water stress by changing
patterns of water availability in many parts of the world (Lobell et al. 2008).
Because of that, the importance of cost analysis of water in the agricultural sector
would increase.
The world’s agriculture, hydroelectric power, and water supplies depend on
different components of the hydrological cycle, including the natural replenishment of surface and groundwater resources (Kang et al. 2009). Fujihara et al.
(2008) pointed out that water scarcity will not occur if water demand does not
increase; however, if the irrigated area is expanded under present irrigation efficiency rates, water scarcity will occur. Moreover, water availability is under threat
from changing climate because of possible precipitation decrease in some regions
of the world. In light of the uncertainties of climate variability, water demand, and
socioeconomic environmental effects, it is urgent to take some measures to use the
limited water efficiently and develop some new water resources (Kang et al. 2009).
The challenges of water scarcity are heightened by the increasing costs of
developing new water sources, land degradation in irrigated areas, groundwater
depletion, water pollution, and ecosystem degradation (Hanjra and Qureshi 2010).
Rosegrant and Cai (2002) estimated that under their baseline scenario, total
global water withdrawals for agricultural, domestic, and industrial use will
increase by 23 % from 1995 to 2025. The availability of sufficient water resources
is one of the major crises with overarching implications for many other world
problems especially poverty, hunger, ecosystem degradation, desertification, climate change, and even world peace and security (Khan and Hanjra 2009).
In China, where more than 300 cities already are short of water, these shortages
are intensifying (Khan et al. 2009). Water resources, critical for irrigation, are
under great stress as populous cities, states, and countries require and withdraw
more water from rivers, lakes, and aquifers every year (Hanjra and Qureshi 2010).
Recent flooding and heavy precipitation events worldwide have caused great
damage to crop production (Rosenzweig 2007). If the frequency of these weather
extremes were to increase in the near future, the cost of crop losses in the coming
decades could rise dramatically. On the other hand, The Fourth assessment report
(AR4) from the IPCC projected that drought-affected areas are likely to increase in
extent in the future, with Europe, the Mediterranean, and southern areas of
Australia at particularly high risk in the summer months (Gosling et al. 2011).
Moreover, significant increases in drought have also been projected for West
Africa, Central Asia, Central America, western Australia, the Middle-East, Indochina, and mid-latitude North American regions (Hirabayashi et al. 2008; Sheffield
and Wood 2008; Sillmann and Roeckner 2008).
In the twenty-first century, global agriculture has met the new challenge,
namely to increase food production for the growing population under increasing
scarce water resources, which can be achieved by improving crop water productivity (Kijne et al. 2003).
1 Strategies for Sustainable Plant Food Production
23