The Economics of Desertification, Land Degradation, and Drought

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Table 2.4—Continued Location 10 20 30 40 50 Tibetan Plateau -0.063 - 0.130 -0.166 - 0.208 - 0.206 Eastern Asia 0.011 0.023 0.053 0.083 0.093 South Asia and Oceania Southeast Asia - 0.011 - 0.016 - 0.026 - 0.031 - 0.009 South Asia 0.022 0.031 0.037 0.032 0.032 Australia -0.082 -0.191 - 0.258 - 0.319 - 0.318 North America Alaska -0.115 - 0.206 - 0.238 -0.241 -0.207 Western North America -0.052 -0.113 - 0.195 - 0.248 -0.279 Central North America -0.108 - 0.199 - 0.264 - 0.325 - 0.376 Eastern North America -0.050 -0.108 - 0.152 - 0.177 - 0.185 Northeastern Canada - 0.181 - 0.315 -0.407 - 0.481 - 0.509 South America Central America -0.060 - 0.118 -0.139 - 0.130 -0.111 Amazon -0.069 -0.125 - 0.172 -0.216 - 0.238 Southern South America -0.034 - 0.090 - 0.155 - 0.214 - 0.258 Source: Sheffield and Wood 2008. Table 2.5—Estimated effect of climate change on drought frequency in 2030 Southeast Asia 38 South Asia East Africa Central America Baseline frequency (1992–2008) 3 7 10 4 Baseline frequency/10 years 1.8 4.2 6.1 2.4 Low impact (percentage change) 0% 0% 0% 0% Frequency/10 years (2030) 1.8 4.2 6.1 2.4 Medium impact (percentage change) 5% 5% 10% 10% Frequency/10 years (2030) 1.9 4.5 6.7 2.7 High impact (percentage change) 10% 10% 20% 20% Frequency/10 years (2030) 2.0 4.7 7.3 2.9 Source: Webster et al. 2008. Types of Land Degradation Land degradation can be classified according to different types: physical, chemical, and biological processes. These types do not necessarily occur individually; spiral feedbacks between processes are often present (Katyal and Vlek 2000). Physical land degradation processes refer to erosion; soil organic carbon loss; changes in the soil’s physical structure, such as compaction or crusting and waterlogging (that is, water accumulates close to or above the soil surface). Chemical processes, on the other hand, include leaching, salinization, acidification, nutrient imbalances, and fertility depletion. According to Hein (2007), soil erosion, whether induced by water or wind, involves translocation of topsoil from one place to another and represents the most important land degradation problem. Pimentel (2006) estimated that about 30 percent of the global arable land has been severely eroded in the past 40 years. Soil productivity is lost through reduced rooting depth, removed plant nutrients, and physical loss of topsoil. One important feature of soil erosion by water is the selective removal of the finer and more fertile fraction of the soil (Stocking and Murnaghan 2005). Figure 2.18 gives an overview of methods used to assess different types of land degradation. Although most of the assessments are done on the local level, some methods are available for assessing types of land degradation on large areas, such as the analysis of vegetation or the monitoring of water turbidity modeling.
Figure 2.18—Methods for the assessment of land degradation Source: Modified from Castro Filho et al. 2001. Note: A penetrometer is an instrument that measures the hardness of a substance. Usually erosion is a natural soil-forming process that can be accelerated by human actions (Katyal and Vlek 2000). Determining factors of soil erosion are rainfall (erodibility), vegetation (cover), topography, soil properties (erodibility), slope inclination, and exposure (sun, shadow), as well as socioeconomic factors like population density and severity of poverty (de Graaff 1993). Soil compaction, another form of physical land degradation, is common in areas using heavy machinery or areas with high livestock density. Waterlogging and salinization are mainly caused through inefficient irrigation systems, where improperly lined canals lead to seepage and result in a rise of water tables. The GLASOD study estimated that salinity accounted for about 4 percent of the degraded land area (see Table 2.1). The usual depth of salts in soils cannot be maintained, and the resulting salinity in topsoils leads to decreased plant growth if it is not diluted or washed away by rainfall (Katyal and Vlek 2000). It is estimated that about 20 percent of irrigated area is affected by salinity (Pitman and Lauchli 2004). Soil nutrient mining is also an important problem in countries that apply limited amounts of fertilizer. Tan, Lal, and Wiebe (2005) estimated that about 56 percent of area planted with wheat, barley, rice, and maize experienced soil nutrient mining, which led to a yield reduction of 27 percent in 2000. Developing countries account for about 80 percent of the global soil nutrient mining. As shown in Table 2.6, in the 1990s, South America and Africa, respectively, accounted for about 50 percent and 34 percent of areas with some form of soil nutrient depletion. However, soil nutrient depletion in Sub-Saharan Africa has been more severe than any in other region due to the limited use of fertilizer (Henao and Baanante 1999). 39 .
Page 1 and 2: IFPRI Discussion Paper 01086 May 20
Page 3 and 4: Contents Abstract vii Acknowledgmen
Page 5 and 6: List of Figures 1.1—Conceptual fr
Page 7 and 8: ABSTRACT Attention to land degradat
Page 9 and 10: ABBREVIATIONS AND ACRONYMS ADB Asia
Page 11: SCAR Soil Conservation in Agricultu
Page 14 and 15: In the present report, the conceptu
Page 16 and 17: Framework: Confronting Action versu
Page 18 and 19: understand these arrangements in or
Page 20 and 21: Figure 1.3—Prevention, mitigation
Page 22 and 23: on assessments at the micro level (
Page 24 and 25: does not clearly distinguish betwee
Page 26 and 27: Figure 2.1—GLASOD (1991) global a
Page 28 and 29: International Earth Science Informa
Page 30 and 31: Box 2.1—Continued Normalized Diff
Page 32 and 33: Figure 2.4—Loss of annual NPP, GL
Page 34 and 35: Figure 2.7—Annual loss of NPP in
Page 36 and 37: Table 2.2—Nitrogen application ra
Page 38 and 39: Figure 2.12—Areas affected by hum
Page 40 and 41: output—which is a selection of su
Page 42 and 43: GLADIS also underlines the linkage
Page 44 and 45: Box 2.2—Continued A map on global
Page 46 and 47: Table 2.3—Global land degradation
Page 48 and 49: Table 2.3—Continued Project and d
Page 52 and 53: Table 2.6—Extent and severity of
Page 54 and 55: National Level Policies As discusse
Page 56 and 57: Such support has also been directed
Page 58 and 59: Migration, either as outmigration o
Page 60 and 61: The preceding discussion shows the
Page 62 and 63: Results Correlation Analysis Consis
Page 64 and 65: Figure 2.23—Relationship between
Page 66 and 67: Effects of Land Degradation On-Site
Page 68 and 69: soils and higher land productivity.
Page 70 and 71: Acknowledging the work of GLADIS, a
Page 72 and 73: health, education, security, enviro
Page 74 and 75: Box 3.1—Recent major economic ass
Page 76 and 77: An appropriate economic tool for a
Page 78 and 79: Figure 3.4—Cost of action and cos
Page 80 and 81: enefit—for example, income. This
Page 82 and 83: Figure 3.6—Ecosystem services fra
Page 84 and 85: Replacement Cost Approaches The rep
Page 86 and 87: Box 3.2—Measuring land degradatio
Page 88 and 89: land degradation and conservation m
Page 90 and 91: Flooding and Aquifer Recharge Richa
Page 92 and 93: year (Diao and Sarpong 2007). Sonne
Page 94 and 95: Bringing together the different cos
Page 96 and 97: This section discusses the most imp
Page 98 and 99: governing land use patterns (Leeman
Page 100 and 101:
promotion of community forest manag
Page 102 and 103:
Box 4.3—Reducing emissions from d
Page 104 and 105:
Soil Nutrient Depletion Soil nutrie
Page 106 and 107:
that the yields of salt-tolerant wh
Page 108 and 109:
Figure 5.3—Forest area as a perce
Page 110 and 111:
Figure 5.5—Per capita water stora
Page 112 and 113:
Introduction 6. CASE STUDIES Five c
Page 114 and 115:
Salinity The effects of salinity on
Page 116 and 117:
Third, to correctly decide which ac
Page 118 and 119:
Costs of Action and Inaction We eva
Page 120 and 121:
The NGOs and religious organization
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have a strong influence on NRM (And
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We estimated the cost of action (de
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Figure 6.15—Costs of action and i
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Of interest to us is the strategy t
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7. PARTNERSHIP CONCEPT The review o
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degradation. All this should be don
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Finally, the global assessment of D
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the experience of and lessons learn
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Table 7.3—Example of E-DLDD resea
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8. CONCLUSIONS Since the publicatio
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lowest in the region. From a socioe
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Table A.1—Land degradation assess
Page 146 and 147:
Table A.2—Continued Author Region
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Table A.3—Continued Author Countr
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Table A.5—Costs of land degradati
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Figure B.1—Land use systems of th
Page 160 and 161:
REFERENCES Abelson, P. 1979. Cost B
Page 162 and 163:
Benin S., E. Nkonya, G. Okecho, J.
Page 164 and 165:
Clark, E. H. 1985. The Off-Site Cos
Page 166 and 167:
De Jager a., D. Onduru and C. Walag
Page 168 and 169:
Foster, V., and C. Briceño-Garmend
Page 170 and 171:
Holden, S. and H. Lofgren. 2005. As
Page 172 and 173:
Lapar, M. L., and S. Pandey. 1999.
Page 174 and 175:
Nachtergaele, F., M. Petri, R. Bian
Page 176 and 177:
Pender, J. L. 2009. “Food Crisis
Page 178 and 179:
Sauer, J., and H. Tchale. 2006. Alt
Page 180 and 181:
Tan, Z. X., R. Lal, and K. D. Wiebe
Page 182 and 183:
———. 2010. “Assessment of L
Page 187 and 188:
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