Mary Seely
Desert Research Foundation of Namibia P 0 Box 20232, Windhoek, Namibia
Introduction
Climate variability, on both a temporal and a spatial basis, plays a central role in determining the livelihoods of a majority of people living in sub-Saharan Africa.
Most recently international media attention has turned to Global Climate Change, El Nind and the droughts of the Sahelian region. Climate variability is not a new phenomenon, however, and people have coped by managing available natural resources, with varying degrees of success, for millennia. While climate variability could refer to all aspects of climate, including temperature, humidity and wind or to an integrated view of all components of climate, rainfall alone is the usual focus of attention, particularly its absence often known as drought, and will be so in this paper.
Temporal and spatial rainfall variability increases as aridity increases. The
consequence is that natural resource managers in arid and semi-arid environments must deal not only with low rainfall but also with highly variable rainfall. Many adaptations have evolved, mainly focusing on below average rainfall, including small- and large-scale movements of people and livestock, variation of crop planting times, and storage of produce for future use. Exceptionally high, rather than low, rainfall occurs less frequently in arid areas so that few if any adaptations have developed other than taking advantage of the diversified resource base that periodically results. Infrequent floods, that fertilise fields and provide fish and increase fish productivity, are one example of the results of high rainfall for which people are usually well prepared. Variability of rainfall in a semi-arid crop-farming area with a high population is illustrated in Figure I.
Adaptations to climate variability differ depending on the time scale of the low rainfall periods as well as the type of natural resources being managed (Olszewski
& Moorsom 1995). Intra-seasonal drought occurs when an insufficient quantity of rain falls over a critical period within a season. Seasonal drought occurs when rainfall over an entire season is well below normal. Multi-year drought adds the
cumulative impact of low rainfall to worsen the impact of successive drought seasons. While climate variability more traditionally is considered to affect crop farmers and livestock herders, there are other consequences and compounding factors.
Figure 1 Rainfall variability in a dry lands cropping area of Northern Namibia (Marsh and Seely 1992).
Definitions of climate variation known as drought
Measurements and descriptions of climate variability are most often based on total annual rainfall or mean monthly rainfall. Often described as a ‘meteorological
drought’, this simple measure is no more than a statistical convention related to the long-term norm. Such measurements are valuable for establishing an objective and general standard that can be related to perceptions and experiences by
affected resource managers and others concerned. In Namibia, the new National Drought Policy and Strategy depends on establishing a quantitative baseline for declaration and management of what it terms ‘disaster droughts’, very low rainfall which can not have been planned for in the normal range of expected climate variation.
A ‘hydrological drought’ refers to the lack of recharge of aquifers, either into groundwater reserves or by runoff into natural or man-made surface reservoirs.
Recharge of aquifers usually results from heavy downpours rather than gentle, soaking rains but also may be influenced by antecedent factors such as vegetation cover, degree of soil saturation and the effects of overgrazing or over-trampling of the aquifer catchment (WET 1999). Other issues affecting ‘hydrological drought’
include lowering of the groundwater table so that even normal rainfall does not cause recharge. Dams and boreholes in the upper catchment of an aquifer may affect the water table downstream increasing the frequency of ‘hydrological
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drought’ in the lower catchment (Olszewski and Moorsom 1995). Managers of water resources must consider all these factors to ensure sustainability of supply.
Figure 2 Maximum rainfall and proportion of rainfall per month varies among years (Marsh and Seely 1992)
‘Agricultural drought’ is the deficiency or absence of rain that affects the normal functions of the agricultural year (Olszewski and Moorsom 1995). This varies among agricultural zones. Crop droughts refer to insufficient rain for at time, particularly during harvest, may also affect total production. Large stock agricultural drought may be positively or negatively influenced by the quality of agricultural and other natural resources to variable rain. Natural resource managers are affected differently depending on the type and condition of resources they are managing. Rainfall is, however, only one of the factors influencing productivity as well as sustainability.
One aspect of climatic variability is little studied with respect to implications for natural resource management - the long-term variability. One data series from western southern Africa indicates changes that persist for decades. Extending beyond the working lifetime of an individual person, adjustments to reasonably abrupt but persistent variations affect agricultural and hydrological sustainability and present unique problems for their management. Under such a situation, even indigenous knowledge applied to traditional management systems in the absence
of population, land tenure or policy framework pressures would not guarantee sustainable natural resource management.
Figure 3 Long term variation in Zambezi River flow measured at Victoria Falls (Pallett 1997).
Natural resource management objectives
Natural resource management objectives vary depending on the resources in question and the degree of entitlement the manager has to these resources, Table 1 summarises three main types of resources that can be considered.
Table 1. Categories of resources of a farming household potentially affected by climatic variation.
PRIMARY NATURAL RESOURCES: land, water, soil, grazing, woody vegetation, wildlife, wild foods
SECONDARY NATURAL RESOURCES: livestock, crops
TERTIARY RESOURCES: cash for sale of natural resources, income from ecotourism, drought relief fodder for livestock, food aid
Entitlement to such resources is often ‘fuzzy’ (Sen 1981) as it may consist of ownership, control, access or simply influence (Seely & Devereux 1996).
Ownership may confer complete control over and access to natural resources, such as in the form of private ownership of commercial farms or in state
ownership of fenced wildlife reserves. Even for the state, however, control may be incomplete despite constitutional ownership, for example, when private land owners lower the water table in catchments of state dams designed for urban supply -
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In common property regimes or at the household level, however, such relationships are more complex. For example, the state may own communal farmland while headmen or absentee livestock owners actually control how the primary resources will be used by livestock or for crops. Individual family members living in the resource management, or even information about impending drought conditions, may be accessible to only some persons involved in natural resource management, often distant from where day-to-day decisions are being made. Fuzzy entitlement relationships, therefore, result in different players having different roles as well as different objectives in terms of natural resource management. These differences are predicated on differing rights, responsibilities and burdens with respect to management or mismanagement of the resources in question which, in turn, are affected, inter alia, by climatic variation.
Similarly, control, access and management objectives vary with respect to primary resources while the effects of their management or mismanagement impinge
differently on various community members. Woodland products, for instance, are more important for the day to day livelihoods of poorer households in the Kavango Region of Namibia than for the more wealthy households in the same village who often harvest them to augment cash incomes. Wealthy households, however, often have the means to collect, consume or sell more woodland products while the burden of their depletion falls on the poorer households who depend on these resources because they have fewer alternatives. When climatic variability is superimposed on this resource management scenario, it is clear that different households, with different managernent objectives, and even household members with different objectives are affected differently (Flower pers. comm.).
Sustainable natural resource management per se is normally secondary to other objectives for resource managers ranging from the national to the subsistence scale. Economic interests, social or cultural interests or simply food usually
represent the primary objectives of people managing natural resources. The poorer the people the lower their interest in and capacity to bear the costs of reduced immediate benefit that usually accompanies sustainable management of resources.
Only managers whose primary needs and objectives are met then consider, if at all, the long term, or sustainable, use of the resources responsible for providing their basic needs. Similarly, considerations of sustainability from outsiders, e.g.
governments or the international community working with peoples affected by drought, usually focus on sustaining populations, or on social or cultural interests or on food for the affected population. Sustainability of natural resource
management is often given low priority when people are subjected to climate variation and particularly drought.
Moreover, climatic variability is just one of a suite of factors impinging on sustainable livelihoods that include policy, political, environmental and social framework, infrastructure, markets, population increase, land tenure constraints and human resource availability. Population increase is often a primary factor exacerbating the effects of climatic variation. While natural resources under one population level may suffice to sustain livelihoods, they may be insufficient for increased population levels. Under such circumstances, the causes of a deficiency in natural resources are difficult to distinguish and climate variability rather than the population increase is usually identified as the primary cause. Overcoming the effects of climate variation rather than the effects of increased population then becomes the objective of the affected resource managers. In contrast to population increase, land tenure constraints are often specifically identified as exacerbating the effects of climatic variability. Resource managers are, however, often politically powerless or otherwise unable to target land tenure constraints so that their objectives again focus on mitigation of the effects of climate variability
A number of causative influences and activities increase susceptibility of natural resources and their management to climate variability, particularly drought, and increase the risks for individuals and groups of people (Seely et a/. 1995). These include factors such as, inter alia:
- increasing population of people and livestock
- changes in demands of rural and urban populations with changing expectations, often superimposed on an increasingly stratified wealth profile
- reaction to climate variation and drought rather than pro-active planning
- provision of artificial water points for ‘emergency’ purposes which then become the nuclei of permanent settlements
- sedentarisation of mobile human and livestock populations - absentee farm management
- fencing under some land-use management practices
- fostering of negative attitudes toward traditional farming practices and promotion of commercial or ‘modern’ agricultural practices.
Unable to address a variety of these root causes of unsustainable livelihoods and resource management practices, individuals, and in some instances institutions, attempt to reduce risk through addressing climate variation while maximising selected outputs.
In Namibia, water is a scarce commodity directly affected by climate variation and potential ‘hydrological drought’ is a frequently looming occurrence. The national and municipal institutions responsible for water management increasingly are preparing for predicted water shortages. Implementation of water demand
management policies and strategies, through appropriate pricing, public awareness 128
and infrastructure improvement and maintenance, reduce the potential exposure of urban populations to risks associated with climate variation (van der Merwe 1999).
Another approach used by water resource managers is to manage variability of hydrological inputs and the aftermath of a hydrological drought, thereby reducing the potential risk to the urban population. ‘Conjunctive use’ of surface storage reservoirs is one such approach (Heyns et al. 1998). At the end of the rainy season, water is pumped from dams with high evaporative potential to those with lower potential while water from open dams is used before groundwater supplies.
Artificial recharge of groundwater from open reservoirs is a second technique used to manage this resource and reduce loss to evaporation, particularly important in dry years.
If water is in short supply, as it is in some areas on a permanent basis, reducing the amount of water resources supplied to consumers is one method used to mitigate the impact of existing and potentially increased deficit. Building dams, to mitigate against variable rainfall in one part of a catchment, often has the side effect of shifting the risks of reduced supply and greater variation on to others downstream in that river catchment. In Namibia, this has frequently been
recorded, as the result of large state dams constructed to supply urban centres as well as small farm dams constructed to supply livestock on commercial farms (Jacobson et a/. 1995).
In the private sector, ‘agricultural drought’ and exposure to the risk of a crop drought may be mitigated against by buying in supplies of grains as soon as the season shows signs of greater than normal climate variation. Commercial
livestock farmers sometimes reduce exposure to climate variability by adhering to suggested stocking rates, despite t.heir questionable applicability, and by
maintaining stores of fodder or grazing reserves. They may mitigate against the impact of immediate risk by selling stock as drought conditions develop. Until recently, they also passed the risk onto the government by demanding drought relief subsidies of various descriptions (MAWRD 1997).
Risk reduction at the household level
At the household level, approaches to risk reduction vary between and within households. Wealthier households are in a better position than poorer households to prepare for drought, to mitigate against its affects and even to shift
responsibility elsewhere including onto the state. Even within households,
different members have different possibilities to ameliorate risk. Absentee, male heads of households are in a far better position than their poorer, often old or very young household members, to address potential risks. Moreover, actions of some household members who have the power to shift or diversify risks, e.g. by sending additional cattle into the rural region, not investing in fertilisers or by refusing to sell livestock as primary resources decrease, increase the effects of climate
variability and vulnerability experienced by other members of the same household.
These inter and intra-household differences, the result of differing entitlements,
mediate the potential impacts of climate variation at the household level and may shift and increase impacts for others.
During an agricultural drought, crop farmers suffer reduced harvests, which means they grow less staple food, earn less cash income from the sale of crops and have an increased need to purchase food. Livestock holdings may be reduced through raising mortality rates as grazing becomes scarce and found at greater distances from water and through inducing ‘distress.sales’ of animals as their owners try to reduce losses or to raise money to purchase food (Naeraa et a/. 1993; Devereux &
Tapscott 1995). An additional effect is reduced employment for agricultural labourers on commercial farms.
Few subsistence farming households are in a position to reduce their exposure to risk accompanying potential climate variation. Pre-drought livestock sales may be encouraged by the authorities, however, the response is usually limited.
Improvement of agricultural extension and provision of rural credit could have an impact if implemented. The National Drought Policy and Strategy emphasises this approach to reducing exposure risk rather than mitigating the effects of drought once it has developed. On the other hand, there are many ‘coping strategies’ or approaches to mitigating the effects of drought which fall into the categories of protecting or modifying food consumption, which are currently practiced (Devereux and Tapscott 1995). When crop production or income declines, households can draw on alternative sources of food or cash to minimise the risk of reduced food consumption. These sources include: sales of livestock, sales of household assets, borrowing (cash or food), informal transfers (remittances) and formal transfers.
Household decision makers may also reduce spending on non-essential items to preserve cash for food. In addition, households may modify their consumption by rationing food or changing their diet. A variety of approaches to reducing or mitigating negative effects associated with climate variability elsewhere in Africa are detailed in Hjort af Ornas (1993).
Lessons learned
Climate variability has a number of implications for sustainable natural resource management on different scales and with differing consequences for risk management potential, as illustrated above. An underlying theme is the
importance of information for natural resource managers operating at all levels.
To address climate variability, resource managers must be proactive and responsive at the relevant spatial and temporal scale. This may range from
conjunctive use of water supply for large urban centres on the inter-decadal scale, to establishing grazing reserves and improving the fertility of soils used for crops over successive years, to sales or movement of livestock as seasonal rainfall proves inadequate. On the other hand, trends such as mining groundwater reserves for non-essential urban consumption or encouraging dependency on a state or shared tractor service decreases the ability to be proactive or responsive and increases susceptibility to climate variation.
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Similarly, diversification of resources used also can contribute to risk reduction. In an urban centre this may be a water supply using groundwater, impounded
ephemeral river runoff, recycling and reuse coupled with strong water demand management, as is found in Windhoek. On farm it may include banking and investing some of the annual cash profit, remittances for rural dwellers, a diversification of livestock and crop varieties and management practices or differing within household primary natural resource uses and management
approaches. These approaches are all, however, dependent on access to relevant information.
Absentee management of natural resources, as is common in rural areas of southern Africa when the household head seeks a cash income in town,
contributes to increased risk from climate variation. This can be seen, however, as a necessary trade-off enhancing diversification of incomes, particularly for poorer rural households.
Land use planning, so that plans for sustainable use of resources are in place, can contribute to reducing risks from climate variation. This can partly help to reduce the disparity between expectations of rural dwellers, many in southern Africa coming out from under the imposition of apartheid, and the realities of farming in an arid, variable climate while population densities rapidly increase. Secondarily, it can contribute to reducing the mismatch between availability of water and grazing.
Overall, a main implication for sustainabte natural resource management in a region where climate variability is the norm, is that modes of integrated management of natural resource users should be better known. Such information can be of use to farmers themselves, to extension and other service providers as well as to
governments and the international community. What is required is a thorough understanding of the successes and failures of current practices, of the approaches to risk prevention, reduction or shifting, and of the effects of variable entitlements on the livelihoods of those faced with drought. When combined with other information-based approaches to natural resource management, such an understanding can make a significant contribution to mitigating the effects of
governments and the international community. What is required is a thorough understanding of the successes and failures of current practices, of the approaches to risk prevention, reduction or shifting, and of the effects of variable entitlements on the livelihoods of those faced with drought. When combined with other information-based approaches to natural resource management, such an understanding can make a significant contribution to mitigating the effects of