In this section, equity issues arising from the use of the three broad methodological approaches are illustrated, drawing on the findings from the completed review.
3.1. Ecosystem-Based Mapping and Modelling: Examples from Latin America and the Sahel
Methods for assessing vulnerability to drought based on the mapping of agro-ecological activities and sensitivities to water stress are relatively well-established after [22
]. These are often used at the local level with participatory assessment methods to assess drought effects on agro-ecological zones and ecosystems [23
]. Numerous examples of agro-climatic or agro-ecological approaches were identified through a keyword search on ‘drought vulnerability assessment’ amongst the peer reviewed scientific publications e.g., [26
]. These approaches are widely used for national level vulnerability assessments for drought as well as other climatic changes and land degradation processes. Often, they focus on mapping a selection of physical and social indicators or indices. Similar mapping and modeling approaches can also be used to map vulnerability at the local level.
The World Meteorological Organization and Global Water Partnership (WMO/GWP) [28
], and International Bank for Reconstruction and Development (IBRD) [29
] described how staff and researchers from national institutions sought to design and roll out standardized programs for drought vulnerability mapping across Mexico. Teams of investigators in each watershed were given standardized guidance prepared by the Instituto Mexicano de Tecnología del Agua (IMTA) to apply with watershed councils. However, due to limited and uneven availability of datasets, they found that they could not apply consistent procedures or methods across the whole country. Progressively, a comparison of the methods used, including various indicators and weighting systems [30
], provided a basis for refinements [31
], and the development of a standardized index for mapping vulnerability to the level of the municipalities [31
Often, vulnerability maps remain qualitative, and do not explicitly provide a value for the potential losses of the productive resources that they identify to be at risk. After droughts have happened, rapid value assessments of losses may be produced retrospectively using available maps and value estimates. For example, UNGRD [33
] identified effects from El Nino in Colombia including impacts on agricultural production value, the number of hectares sown per department and GDP per department [34
]. Such assessments provide a powerful case for preventive actions. Many other examples are available in the literature on drought impacts. See: https://www.gfdrr.org/en/publications
However, when there is no emergency imperative to justify them, quantitative economic assessments of vulnerability can be considered controversial and raise very difficult questions about equity issues.
It is important to realize that the vulnerability of land uses and production systems belonging to groups whose interests are politically and economically well-established is often more readily mapped and assessed than those of more marginal groups. This means that the value of the economic activities and contributions of the most vulnerable people can easily be overlooked in land- and ecosystem map-based assessments. For example, across much of the Sahel, land may be used by both settled farmers and migratory pastoralists who come and go on a seasonal basis [35
It is relatively straightforward to map the land uses and production systems of those with secure land tenure, such as some crop farmers, and to model their propensity to be affected by changes in productivity under varying climatic extremes. However, where there are several different user groups that must continuously renegotiate and share access to the land on a seasonal basis, droughts may affect access to resources for some groups more than others, and in ways that are more complex than ecological maps and decision-support modeling tools would anticipate.
Groups that are weaker, financially, or politically, or which entrust the management of land to others for part of the year, may return to find their access to resources more reduced during drought. Assessments that rely on physical mapping and modeling alone will not capture this differentiated vulnerability. Indeed, if the maps show only the claims of the groups that have permanent access rights (tenure), the existence of these maps themselves can be used to exclude the marginal land users. This will further perpetuate and deepen unequal vulnerability to drought. In societies where men are more likely to own land than women, approaches to vulnerability assessment that rely on land-based mapping techniques will also overlook women’s resource uses and economic activities in other related sectors such as postharvest processing, hospitality or other associated professions.
In some cases, it is possible to connect (agro-) ecological maps and models to additional contributions to the economy that will be made via the value chains that they create for processing, transportation, demand for agricultural inputs, etc. It may also be possible to model environmental externalities associated with agro-chemical use, groundwater depletion, land tenure, access to capital and other effects of ecosystem management. A further range of methodological issues surrounds the conversion of effects on physical production systems into economic effects on households, regions and national economies. In some cases, these will also interact with global economic processes. Additional methodological questions concern the prediction of future economic value and prices.
The more stages, products and values that are included in the model of a land-based production system, the more it may be necessary to accommodate complexities and uncertainties. To begin with, understanding the vulnerability to drought of a cropping system producing forage or other crops is simpler than it is for a livestock production system. This is because the livestock production system model must include possible climatic effects not only on forage production, but also on livestock health and nutrition. To capture these more complex processes and interactions will require the layering of a range of different methods, modelling tools and databases. If the land-based production systems are seen as part of a larger ecosystem and economy including urban areas and other associated activities, this will introduce many more layers of complexity and uncertainty to a land- or ecosystem-based assessment of vulnerability.
3.2. People-Centred Livelihoods Assessment Approaches: Examples from the Horn of Africa
Well-established rapid appraisal methods provide a way for community groups to document the effects of drought. (See Appendix A
) Consistent iterative assessment and validation of results can guide an objective qualitative understanding of the nature of drought impacts and vulnerability. In Ethiopia and Kenya, qualitative findings generated in this way have been compared to quantitative data on household characteristics generated via programs such as the Productive Safetynets Programme (PSNP) in Ethiopia and the Hunger Safety-nets Programme (HSNP) in Kenya, together with data on child nutrition collected through the national early warning system for drought monitoring in Kenya [36
Efforts to assess the economic losses associated with drought in this region e.g., [38
] routinely refer back to an impact assessment that was conducted following the 2008–11 drought [39
], which identified the values of lost production, productive assets, basic services and living conditions from the Kenyan economy at Ksh 968.6 billion (US$
12.1 billion), and the damage in terms of loss of economic growth at 2.8% per year for three years. The productive activities and assets that were considered most-affected by the drought were livestock raised in the extensive grazing systems in the drought-prone areas. However, in 2011, the value of these assets to the national economy was systematically underestimated within the national statistical data collection systems [40
Since the 2011 drought, national drought management responses have been strengthened and early warning systems have been put in place at the national level in Kenya [41
] and regionally [43
] to trigger actions based on the observation of drought conditions. A series of assessments [44
] have explored the returns to local livelihoods that can be secured through community-scale investments to reduce vulnerability through supplementary feed distribution, rehabilitation of water pans, micro-basins, micro-credit and community institution-building for rangeland management, amongst others.
Based on this, some commentators have argued that drought management responses are improving [36
]. On the other hand, over the same period on the larger catchment scale, the flows of water to the drought-prone areas of northeast Kenya have reduced, leaving the downstream populations more exposed to drought. This growing systemic problem requires a more proactive approach [19
]. The increasing upstream extraction is illegal, and the downstream community are considered to have a right to access sufficient water to meet their basic needs. When they cannot do so, their livelihoods are threatened, and they are exposed to higher levels of risk during drought. Similar increases in catchment-level inequalities in access to water have been observed in other parts of the Horn of Africa, as some communities are able to invest in improved water supply infrastructure, while others who are located downstream receive reduced flows [49
The international humanitarian community often pays a high price for drought relief, and yet still cannot restore the livelihoods that are lost. The growing upstream–downstream inequalities have been considered by some national development planners and economists still to be justified in light of the recognized economic value of crop production in the upstream areas that are irrigated using the extracted water [51
]. By some assessments, this contributes more to the national economy than maintaining the downstream populations and their extensive livestock raising activities. Although such justifications have been contested, the problem is that the public authorities and local enforcement officers are not empowered to prevent private extractions in the upstream areas because some of the land-users concerned are more powerful than they are.
When the most vulnerable people in the downstream areas lose their livelihoods during drought, this is only the beginning of the losses. Trades and value chains that are destroyed alongside the livelihoods of the vulnerable communities have attracted increasing attention and estimates of their net worth are growing. Deepening vulnerability and exposure to drought cause further draining of the local economy due to increasing uncertainty, insecurity, transaction costs, underinvestment and outward transfer of resources (including people and currency as well as natural assets) [49
]. In light of these problems, it is important that rapid livelihood-focused vulnerability assessments be integrated with drought risk assessments at other scales. It is also important that assessments of the immediate humanitarian responses to drought do not overlook effects on the sustainable management of hydrological systems.
3.3. Basin or Catchment Level Resource Accounting: Examples from India
Areas with greater water utilization can be considered more vulnerable to drought than those with low water utilization [53
]. Water stress occurs when the ratio of water extraction is high in relation to resource availability, as happens during hydrological drought. Water stress and scarcity during drought can cause the costs of accessing water to escalate, which will disadvantage lower income groups. Sometimes, hydrological drought and water stress may be temporary phenomena. But if water extractions reduce flows in surface water bodies and cause the water table to be lowered, this will alter the availability of water in the soil profile as well as surface water bodies and subsurface reserves unless/until the systems are replenished. Water stress can be exacerbated by rising water demands, causing a situation where insufficient water resources are available to meet demands for water for agricultural and other uses [54
Basin- or catchment-level water resource accounting enables assessments to be made of vulnerabilities and exposure to drought risks due to water stress. Various water accounting and balance modeling approaches focus on the available volumes of water in different parts of the ecosystem (see: https://seea.un.org/content/seea-water
]. This supports comparisons of the volumes of available water to the volumes extracted [58
]. Since, as described in the previous section, increased or reduced availability of water in one part of a basin can affect flows and availability in other areas, assessments should focus on hydrological units (basins or catchments), rather than on administrative units. Basin-level water accounts can be calculated on an annual basis, based on the volumes of precipitation and extraction. However, these accounts should also consider the opening balance of water volumes stored in surface water bodies and underground.
In India, following a severe drought in 2015–2016, accusations of inconsistent and unfair use of drought emergency measures led the Supreme Court to order that the national Drought Management Manual [59
] be revised to include objective scientific measurements that could be used to assess drought conditions equitably and uniformly in all parts of the country. In addition to rainfall and agricultural conditions, water storage levels in reservoirs, surface water and groundwater were to be measured as indicators of drought.
Whereas earlier in the century, droughts were buffered by stored groundwater reserves, in many areas, these reserves have now been depleted as part of the coping strategies for previous droughts. Where the stores of water cannot be replenished, this affects ongoing vulnerability to drought. Changing hydrological conditions in various parts of India have reduced water levels in the rivers and surrounding subsurface areas. Where water tables have fallen, flows of groundwater that once fed into riverbeds are no longer contributing to the river flow volumes. Now, instead, water seeps out of the riverbeds into soil that has been left dry due to the groundwater deficit.
The Supreme Court has also been called upon to make rulings about the minimum flows of water from one state to another during droughts. But no court can order water not to flow out of a porous riverbed if the water-table is depleted. This depends on the local environmental conditions, which will vary temporally and spatially. It is very difficult for states to regulate the competing demands of different water users. In the 2016 drought, the State of Maharashtra was forced to curtail nonessential uses of water (e.g., for watering cricket-pitches), but it still could not prevent overextraction of water by other groups, including sugar-cane farmers, from causing shortages of water for drinking and other basic needs [61
To reduce the hydrological deficits and increase the rate of groundwater recharge, water harvesting programs, both rural and urban, have been launched in many parts of India [62
]. Even though the wider basin or catchment scale is important for understanding the overall effects on the water balance, monitoring and assessments of water levels to ascertain vulnerability to drought can be carried out at the local (village) level. The implementation of water harvesting programs to reduce localized vulnerability can also be practiced at this level, where communities are sufficiently aware, organized and empowered to do it. It is important to recognize that the feasibility and effectiveness of systems for local monitoring and management of hydrological vulnerability to drought depend on local people and their livelihoods; therefore, these types of assessments cannot be divorced from the people-centered and livelihood-oriented approaches described in the previous section [63