Change to Sustain Food Security

Peter Droogers,1 Jos van Dam,2 Jippe Hoogeveen3 and Ronald Loeve1

1FutureWater, Arnhem, The Netherlands; 2Wageningen University, Wageningen, The Netherlands; 3FAO, Rome, Italy

Introduction

Producing sufficient food to sustain the growing world population is one of the key challenges for now and for the coming decades. According to a study recently presented by the Food and Agriculture Organization of the United Nations (FAO), about 799 million people in the developing world do not have enough to eat and another 41 million in industrialized countries and countries in transition also suffer from chronic food insecurity (FAO, 2002a). More than half of these undernourished people (60%) are found in Asia, while sub-Saharan Africa accounts for almost a quarter (23%). In terms of the percentage of undernourished people of the total population, the highest incidence is found in sub-Saharan Africa, where it was estimated that one-third of the population (34%) was undernourished in 1997-1999. Sub-Saharan Africa is followed by South Asia, where 24% of the population is undernourished (Fig. 3.1). However, significant progress has been made over the last two decades: the incidence of undernourishment in developing countries has decreased from 29% in 1979-1981 to 17% in 1997-1999.

The World Bank estimates of the prevalence of extreme poverty are based on the distribution of household expenditure on consumables (Chen and Ravallion, 2000), while the FAO estimates are based on the distribution of household food consumption and availability. World Bank indices indicate in general higher undernourishment than FAO ones (Fig. 3.1), but there is a positive and close relationship between food consumption and expenditure on consumables in low-income households.

Vorosmarty et al. (2000) argue that the impact of climate change on water and food will be relatively small in comparison to the impact of changes in population and socio-economic projections. However, changes in population and socio-economic issues are gradual and therefore easier to cope with. Climate change includes such a gradual change as well, but is expected to increase extremes substantially.

This chapter will concentrate on the impact of climate change on food and water issues. An overview of global issues and trends will be followed by a more in-depth © CAB International 2004. Climate Change in Contrasting River Basins

Fig. 3.1. Incidence of undernourishment and poverty according to FAO and World Bank (Chen and Ravallion, 2000) definitions.

analysis of field-scale impact and adaptation strategies for the seven basins in the ADAPT context. The field scale is of paramount importance as this is the scale at which food is actually produced. The relation with the basin scale will be discussed, but the subsequent basin chapters (Chapters 5-11) will provide more detail. The field-scale analysis will be oriented towards comparison of the seven basins.

Global Food Issues

Current situation

Food trends in the developing and developed world have shown very different patterns over the last 30 years. Overall, food production is steadily increasing, especially in the developing world (Fig. 3.2, top). Food production per capita, however, is not increasing in the same manner, especially in the developing world (Fig. 3.2, bottom).

An enormous amount of water is required to produce food. FAO's AQUASTAT indicates that from all water diverted, 69% is used in irrigation and 10% and 21% for domestic use and industry, respectively (FAO, 2003b). These data are based on withdrawals and not on consumption. Since return flows from domestic use and industry are in general high and can be reused, actual consumption from agriculture will be even higher in comparison to other sectors. It is estimated that in developing countries irrigated agriculture accounts for about 20% of all cultivated land. Of the total amount of agricultural production, 40% originates from irrigated land, while for

Fig. 3.2. Global trends in food production over the last 40 years expressed as total food produced (top) and per capita (bottom). Depicted figures are indexed with the period 1961 set as 100.

cereals as much as 60% of production originates from irrigated agriculture (FAO, 2002b).

A study recently presented by Shiklomanov (2003) used a modern assessment framework to assess the state of the world's water resources. The study focuses not only on water availability now and in the future, but also includes estimates of water withdrawals and consumption over the last 100 years. Figures presented in this study for the year 2000 compare quite well with the AQUASTAT data that show a withdrawal for irrigation of about 66% of total diversions (Fig. 3.3). In terms of consumption, the

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Fig. 3.3. Dynamics of water withdrawals (top) and consumption (bottom) per sector. (Source: Shiklomanov, 2003.)

agricultural sector is responsible for 84%, while figures for domestic use, industry and reservoirs are 4%, 2% and 10%, respectively. The substantial consumption by reservoirs is often ignored, but is estimated to be even higher than consumption by domestic use and industry together. The total storage capacity of all reservoirs in the world is approximately 6000 km3, almost three times the total annual withdrawals in the world.

Over the last 100 years agriculture has always been the dominant user of diverted water (Fig. 3.3). Since 1950, diversions for domestic use and industry are rising, but consumption is still low in comparison to agriculture. However, it should be considered that water quality requirements will be different for the three sectors considered. For example, water quality requirements will be much stricter for domestic use than

Fig. 3.4. Percentage of water consumption from total water resources by natural-economic regions of the world in 2000. (Source: Shiklomanov, 2003.)

for agriculture. Looking at the spatial distribution, the drier regions of the Northern Hemisphere currently consume a vast amount of their fresh water resources (Fig. 3.4). It is alarming, specifically in China, India and Pakistan, that population growth is high and it is uncertain whether food security can be sustained and enhanced considering future water requirements.

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