Survival in the Sahel

More documents

Recommendations

Info

5 Climate and Natural Resources 5.1 Climate While temperate zones nae sufficient rainfall to support agriculture throughout the year, the situation in the Sahel, with its tropical semi-arid climate, is wery different. There are no noticeable seasons that can be defi ed by temperature. Differences in temperature are more likely tl) occur between day and night and between lowland and highla nd areas than between summer and winter. The three- to fourmmnth rainy season occurs during the summer from June to Septe nber, with rainfall ranging between 200 and 600 mm. Because of intense solar radiation and high temperatures, however, much of this precipitation evaporates before it can be used for agriculture. There is sufficient humidity for agriculture for only two to four months during the year, with dry months predomir ating the rest of the time. The Sahel's climate is grclatly influenced by global wind circulation patterns, which determine periods of rain and aridity in the region. It is worthwhile t,iking a brief, closer look at this process because it plays such a decisive role in the Sahel.1 7 Precipitation in the intertilopical convergence zone (ITC)I 8 has a major influence on the region's climate. Trade winds in the equatorial latitudes converge toward this zone. The zone itseif migrates northward and southward with the seasons. A belt of moist air follows the ITC's mover ient. Precipitation in the convergence zone can fall at the equi tor in all seasons. A period of summer precipitation occurs in iistant tropical zones, but in the desert the climate is continually irid. In winter the Sahel is subj{ct to the influence of the northeast trade winds, which are hot nd dry as a result of their long journey over the desert. Precipitation is rare. The dry season grows longer toward the northe n part of the Sahel. 27
At the height of summer the sun is vertically overhead at the northern tropic in the middle of the Sahara. Following the sun with a certain time lag, the ITC migrates north to about the 15th or 16th northern latitude, the areas north of the Sahel. This causes winds from the southwest to converge toward the Sahel. These winds absorb humidity over tropical waters in the Gulf of Guinea, and, as they move to the northeast, they bring long-awaited rain to the Sahel. But even more critical for agriculture than the actual amount of rainfall or change of seasons is rainfall variability. The ITC moves irregularly, thus making precipitation variable. Annual variations of up to 50 percent can occur, depending on how far this zone of converging air masses 9 advances to the north. 1 Rainfall becomes less certain toward the Sahara. In European latitudes, a year with 100 mm less precipitation than normal will hardly affect harvests. But in the Sahel, a drop of this magnitude puts the amount of rainfall below the 500 mm minimum necessary for rainfed agriculture, causing harvests to fail. Figure 2 shows rainfall variability in the Sahel from the start of this century. It illustrates that years of above-average and below-average rainfall tend to come in clusters. If several dry years occur consecutively, food supply problems increase dramatically. The people of the Sahel can survive one year of failed harvest without major supply problems, provided that reserves are sufficient. But they cannot survive several consecutive years of harvest failure, such as during the long drought from 1968--73. Climatic history and its present-day effects Like all the earth's regions, !he Sahel has been subjected to repeated climatic fluctuations throughout its history. Cold and warm and dry and moist periods have altered the face of the region many imes. Figure 3 illustrates the fluctuations that have taken place over the last 18,000 years. Approximately 20,000 years ago the Sahara expanded south-ward into the current Sahel zone during a pronounced dry period. Rivers dried up, vegetation died out, and sand dunes were formed. About 15,000 years ago climatic conditions began to 28
Page 1 and 2: Survival in the Sahel An ecological
Page 3 and 4: Survival in the Sahel An ecological
Page 5 and 6: Contents Foreword ix Introduction 3
Page 7 and 8: ,j The Political Situation 125 4 En
Page 9 and 10: Appendix Lessons Learned: A Private
Page 11 and 12: deemed to have a better chance of s
Page 13 and 14: of this book is to encourage intere
Page 15 and 16: Introduction
Page 17 and 18: the obstacles are becoming almost i
Page 19 and 20: tion is inappropriate, for progress
Page 21 and 22: Figure 1 The Sahel zone Mauritania
Page 23 and 24: 2 Historical Overview The history o
Page 25 and 26: Trade also demanded a division of l
Page 27 and 28: 3 Population 3.1 Demographic develo
Page 29 and 30: However, only a small portion of th
Page 31 and 32: Table 2 Urbanization in the Sahel (
Page 33 and 34: Table 3 Economic and social develop
Page 35 and 36: increase in food imports in 30 year
Page 37: esult that already scarce resources
Page 41 and 42: Figure 3 Climate and the environmen
Page 43 and 44: half of what it had been ft) 1983,
Page 45 and 46: 5.4 Vegetation As precipitation inc
Page 47 and 48: Overuse of the remaining forest and
Page 49 and 50: degradation has at least had simila
Page 51 and 52: Biological and natural resources (i
Page 53 and 54: In some cases Sahelian governments
Page 55 and 56: in the Sahel. At least, this is the
Page 57 and 58: that rainfall was becoming more sca
Page 59 and 60: good thanks to abundant rainfall in
Page 61 and 62: for combating desertification6 and
Page 63 and 64: per sq km under present land-use pr
Page 65 and 66: which allowed soil fertility tobe r
Page 67 and 68: ists in the Sahel regard cattle as
Page 69 and 70: in the Sahel by 30 ;ercent. This me
Page 71 and 72: 7 Women and the Struggle for Surviv
Page 73 and 74: harvest, even if there wasn't much
Page 75 and 76: absent for brief or prolonged perio
Page 77 and 78: care if women and children suffer."
Page 79 and 80: the process. Hopefully, this new as
Page 81 and 82: Women have gained self-respect and
Page 83 and 84: 8 Sustainable Development Although
Page 85 and 86: with the drought of 1968-73, which
Page 87 and 88: The agroforestry example clearly il
Page 89 and 90:
factor is that NGOs are less bureau
Page 91 and 92:
Conservation effects • less water
Page 93 and 94:
zations will also be required to ac
Page 95 and 96:
series of drought-related famines t
Page 97 and 98:
years-not always consistently over
Page 99 and 100:
cooking or preparation time. High y
Page 101 and 102:
People and resources.As discussed i
Page 103 and 104:
important) problems thai: remain to
Page 105 and 106:
in Agricultural Research (SACCAR),
Page 107 and 108:
majority of the varieties and techn
Page 109 and 110:
mation sciences, as well as on the
Page 111 and 112:
Notes I Economic Commission for Afr
Page 113 and 114:
Entwicklung." Hoffmann und Campe. H
Page 115 and 116:
and international aid organizations
Page 117 and 118:
83 See Baldwin, S. et al., "Improve
Page 119 and 120:
Rural Development in Subsaharan Afr
Page 121 and 122:
I Mali: A Typical Sahelian Country
Page 123 and 124:
1 Geography and Ethnic Composition
Page 125 and 126:
Today pirogues (traditional wooden
Page 127 and 128:
a "caste" system, is disintegrating
Page 129 and 130:
Cotton is Mali's most important exp
Page 131 and 132:
Table 7 (cont'd) Foreign Trade' Exp
Page 133 and 134:
zations such as the United Nations
Page 135 and 136:
een dismissed by the previous gover
Page 137 and 138:
of charcoal and wood-burning stoves
Page 139 and 140:
impossible to avoid. Infrastructura
Page 141 and 142:
5 Agriculture The performance of Ma
Page 143 and 144:
Figure 6 Mali's desert zone, ened w
Page 145 and 146:
In the area around Gao 1,750,000 he
Page 147 and 148:
f.ig 4 re 8 Mali's river basins Nig
Page 149 and 150:
Figure 9 Mali's savanna zones dry s
Page 151 and 152:
variability. Maize also requires ce
Page 153 and 154:
was obliged to sell it at the low o
Page 155 and 156:
spite of this important development
Page 157 and 158:
ally not suited to the new environm
Page 159 and 160:
most important cereal crop in the w
Page 161 and 162:
5.7 Millet and sorghum: supply and
Page 163 and 164:
cities are employed outside the hom
Page 165 and 166:
Small farmers in Mali want to minim
Page 167 and 168:
istles and husk,, and dark husks an
Page 169 and 170:
just to keep up with current and fu
Page 171 and 172:
production of millet and sorghum in
Page 173 and 174:
Swiss CIBA-GEIGY Foundation for Coo
Page 175 and 176:
station produces basic Toroniou see
Page 177 and 178:
als, and trace elements. Such defic
Page 179 and 180:
" During planting and after harvest
Page 181 and 182:
Notes I All figures used in this ch
Page 183 and 184:
35 See Chinsman, B., Op. cit. 36 37
Page 185 and 186:
II Conclusion
Page 187 and 188:
moved, first to guarantee survival
Page 189 and 190:
agricultural development. Examples
Page 191 and 192:
Notes 1 See also McNamara, R., Afri
Page 193 and 194:
LESSONS LEARNED: A PRIVATE-SECTOR F
Page 195 and 196:
internal review of the situation, t
Page 197 and 198:
Repeatable Lesson: The creation and
Page 199 and 200:
station. Animal traction training t
Page 201 and 202:
farm and 3tation fields On-station
Page 203 and 204:
Table 1.Blueprintof the technology
Page 205 and 206:
Repeatable lessons: The definition
Page 207 and 208:
ochure and poster (in both the Fren
Page 209 and 210:
Rational use of manure and compost.
Page 211 and 212:
Over the long run it is likely that
show all

Survival in the Sahel

Create successful ePaper yourself

Delete template?

Save as template?