Anthropogenic droughts are expected to exacerbate water inequalities in postcolonial cities

23 There are growing concerns about the impacts of climate change on equitable urban 24 development. As cities are becoming increasingly exposed to anthropogenic droughts, stakes 25 are particularly high in contexts of severe vulnerability. Yet, the impacts of future urban 26 droughts and the societal responses they will elicit remain poorly understood. Here we 27 develop social-environmental scenarios of anthropogenic drought-related impacts in 28 postcolonial cities, characterized by highly uneven development and differentiated levels of 29 vulnerability. We show how unprecedented droughts are expected to polarize existing 30 inequalities in water access and well-being across genders, race and socio-economic groups. 31 Specifically, unprecedented droughts will likely exacerbate spatial inequalities, generate 32 localized public health crises, and regress development progress in water access. These 33 results suggest that effective climate policies must address water insecurity and other pre34 existing inequalities, and develop equitable water conservation measures to ensure effective 35 adaptation to future unprecedented extreme droughts. 36


Maputo is likely to face unprecedented droughts 95
For Pillar 2, we note that Mozambique ranks amongst the world's most vulnerable countries 96 to climate change 34 and has experienced repeated severe droughts in recent decades 35 , which 97 have been especially frequent in the central and southern parts of the country 36 . These 98 extreme events have occurred on the background of a multi-decadal drying trend (e.g. 37 ). 99 Focusing on the Southern part of the country, where Maputo is located, the latest generation 100 of global climate models points to a future aggravation of the regional risk of extreme 101 meteorological and agricultural drought conditions 38 . Regional climate simulations using 102 precipitation and evapotranspiration jointly to diagnose drought, support these conclusions 39 . 103 There are large uncertainties in future climate projections of precipitation, and diagnosing 104 drought often requires considering additional variables -such as evapotranspiration -which 105 bear their own uncertainties. Nonetheless, the ongoing climate trends and numerical 106 projections of future climates all point to the possibility that Southern Mozambique may be 107 affected by a future, unprecedented drought with a higher likelihood than one may expect 108 from a statistical analysis of historical data series. Moreover, Maputo and its surroundings 109 have emerged as a regional drought hotspot over the last several decades (see Methods). 110 race, class, variegated citizenship, heterogeneous infrastructure and vulnerability 120 conceptualized by critical scholars (Pillar 1). Colonial Maputo was grounded on principles of 121 racial segregation that generated spatial, economic and social inequalities. Due to this 122 heritage, processes of marginalization and dispossession from basic services persist to date. 123 Housing and sanitation policies continue to marginalize lower-income groups, which suffer 124 the most from significant infrastructural deficits and absence of property rights 41,44-47 . 125 Service configurations reflect these uneven developments (Figure 2a). The water utility 126 Águas de Região de Maputo (AdeRM), which relies on surface water from the Umbelúzi 127 river, stored in the Pequenos Libombos dam, has for decades focused on serving higher 128 income residents in the so-called cement city. Whilst water coverage has significantly 129 increased over the past decade 48 , reaching approximately 63% of the city 47 , quality of the 130 service varies across neighborhoods. Recently developed outer peri-urban areas, inhabited by 131 middle income residents, are primarily supplied by over 800 highly-skilled, small-scale 132 private operators that undertook large investment to develop decentralised networks that 133 increasingly mimic the formal water utility 49,50 . These are regulated by the government, who 134 controls rates of groundwater abstraction, water quality and pricing regimes 51 . In contrast, the 135 poorer urban belt neighborhoods rely on self-supply, household water resales or the formal 136 water utility, which is often unable to deliver the same quality of service offered to 137 neighborhoods in the city center 48 . 138 The sanitation landscape is even more unequal. A minority of the population (9 percent) 139 afford higher rates will likely continue to consume at unsustainable rates, thus remaining 169 more water secure. 170 Prolonged water shortages are expected to exacerbate other urban inequalities (Figure 3). 171 From Pillar 1 (Theoretical synthesis) and 3 (Precedents in Maputo) we note that women will 172 likely be disproportionately burdened with the task of finding alternative water sources, with 173 consequences on their employment and income, physical and psychological stress associated 174 with both fetching and not being able to fetch water, and increased risks of violence if 175 sourcing water in the dark or from distant locations. An unprecedented drought might 176 exacerbate food-insecurity of lower income households due to both inflated food prices and 177 the impact of water rationing measures on the ability of lower income residents to maintain 178 their vegetable urban gardens. This, in turn, is expected to increase residents -and 179 particularly women's -vulnerability to widely spread diseases such as HIV 54 . Last, 180 prolonged shortages will most likely exacerbate water-related health risks and generate 181 unprecedented public health crises, largely concentrated in low-income neighborhoods. 182 Drawing on Pillar 3 (Precedents in Maputo), we infer that outbreaks of waterborne diseases 183 and malaria cases will be concentrated in areas with the most significant infrastructure 184 deficits. Chronic water shortages might force residents to resort to unimproved sources such 185 as river streams or to cut pipes to access water from the mains, thereby increasing risks of re-186 contaminated drinking water. Low-lying neighborhoods served by pit latrines will likely be 187 the most at risk. These areas are expected to simultaneously experience prolonged water 188 shortages and more frequent flash floods, because drought events reduce the capacity of soil 189 to absorb water. This will probably increase risks of fecal contamination of drinking water 190 sources and, in turn, waterborne diseases. Moreover, storage practices of low-income 191 dwellers relying on uncovered water facilities located near humans, can increase risks of

Reversing progress in water access or vicious supply-demand cycle? 194
Global political economy is expected to significantly shape the Mozambican government's 195 response to the drought, which largely depends on its ability to access global capital. As this 196 outcome is largely unpredictable, we consider a scenario in which the government does not 197 have access to global capital and one of large capital inflows. In the first scenario, the recent 198 corruption and hidden debt scandals 55 will continue to limit the Mozambican government's 199 access to global capital and the government is unlikely to have the resources to develop large-200 scale infrastructures to increase supply. Based on Pillar 3 (Precedents in Maputo), we predict 201 that the pressure to manage a limited supply for existing customers will constrain the water 202 utility's ability to expand services to unserved urban populations. The city center, inhabited 203 by high income populations, will likely continue to receive water from the water utility, 204 whilst low-income peri-urban areas served by the water utility will suffer from increasing 205 water shortages. As a result, residents will perform different forms of 'going off the grid': a 206 synergistic application of SEEAs Pillars suggests that those with access to land in areas with 207 high water table and financial resources will opt for developing alternative or additional 208 water sources, including boreholes, larger storage tanks and rain-tanks. Those in proximity of 209 areas served by small scale providers that provide more reliable services will add a second 210 connection to augment water availability for the household, whilst others will have to revert 211 to buying water from communal water points or private boreholes or to rely on unimproved 212 water sources. These coping strategies, alongside rapid urbanization, will reverse progress in 213 water access achieved by the service provider over the past decade and increase 214 fragmentation of services in Maputo. For those who can integrate household water sources, 215 this process will ultimately lead to increased resilience, whilst for those who cannot afford 216 access to safe alternative sources, the process of going off the grid will lead to increased 217 vulnerability. 218 In an alternative scenario, access to global capital will allow the government to implement its 219 10-years Capital Investment Program aimed at enhancing water security and resilience to 220 climate change by expanding water supplies through the construction of large water 221 infrastructures. Based on Pillars 1 (Theoretical synthesis) and 4 (Conceptual transfer from 222 Cape Town), we suggest that in response to an unprecedented drought, Maputo will enter a 223 vicious cycle of water supply expansion. In the aftermath of a drought event, the water utility 224 and residents will return to 'business as usual' management and consumption practices, 225 characterized by over-allocation to and overconsumption by elites, rather than conservation 226 practices. These practices will be sustained by the increase in water supply, financed through 227 global capital. The government will develop large scale infrastructures that will meet the 228 growing demand and allow to pursue network expansion without addressing inequalities in 229 access and unsustainable consumption patterns. Paradoxically, this increment in water 230 supplies will increase the city's vulnerability to drought events. Development of large water 231 infrastructures will generate a false sense of security, also grounded on the expectation that 232 the city will face droughts of similar intensity to the past, rather than unprecedented in nature. 233 This assumption will lead to increased consumption patterns that in the long term will 234 reproduce water stress conditions and force the government to reactive responses to future 235 drought events. 236

Intra-urban and inter-national water conflicts 237
Unprecedented droughts might increase the likelihood of water-related conflicts across intra-238 urban spaces and water providers, as well as among riparian states. Water shortages will 239 trigger both households and some providers to access new water sources, with risks of 240 overexploitation and increased competition over available water resources. Intra-urban 241 conflicts could be generated by the increased reliance on groundwater resources by the water 242 utility. We note from Pillar 3 (Precedents in Maputo) that the water utility will likely identify groundwater as the short-term and most affordable solution to cope with the effects of a 244 drought event. Increased reliance on groundwater resources is expected to exacerbate 245 saltwater intrusion in coastal areas 56 and, in the longer term, reduce water availability and 246 lower the groundwater table, causing some boreholes to dry up. The reduced quality and 247 quantity of groundwater availability will extend the impact of the water crisis to previously 248 buffered areas, exacerbating the existing tensions among providers relying on this water 249 source. Conflicts with small-scale water providers (SSIPs) are also expected to be 250 exacerbated by the government's plan to expand services to unserved areas, thereby shrinking 251 SSIP market and income. 252 In the past, the assumption that in international river basins characterized by growing water 253 uses or stress, cooperation efforts would prevail over conflicts has held true for the Incomati, 254 Umbeluzi and Maputo rivers 57,58 . However, Mozambique's plans of developing large 255 infrastructures on these basins in combination with a future extreme drought might reduce the 256 ability and willingness of riparian South Africa and Swaziland to reach consensus on water 257 allocation and on how to cope with multiple and conflicting demands. As the Maputo river is 258 less developed in terms of dams and water allocation, tensions are more likely to arise on the 259 Umbeluzi and Incomati river. The Umbeluzi river is currently the source of a large irrigation 260 scheme in Swaziland and of several smallholder farmers in Mozambique. The Incomati river 261 is the selected site for one of the largest dam projects of the Mozambican government. An 262 unprecedented drought could lead to tensions over water allocation and priorities among the 263 three countries. 264

Conclusions 265
We developed scenarios of urban droughts in post-colonial cities, characterized by highly 266 unequal development, using the city of Maputo, Mozambique, as a case-in-point. We have shown that the impact of present and future droughts can only be understood in relation to the 268 colonial history of these cities. The design of the infrastructure, its purposes, and the heritage 269 of the colonial urban form crucially determine what remaining without water -or Day Zero -270 means for different citizens. As shown by our scenario, spatial and social inequalities, 271 including access to basic services, well-being, gender and socio-economic status generate 272 differential vulnerability to unprecedented extreme droughts. If future policies neglect the 273 heterogeneity of water insecurity and other pre-existing inequalities, only a small part of the 274 urban population will effectively cope with and adapt to future drought events. High levels of 275 vulnerability to droughts are bound to be continuously reproduced or exacerbated if spatial 276 and socio-economic economic inequalities are not addressed. In parallel with this, all actors 277 need to account for the changing physical-environmental context of urban droughts. The 278 ongoing climate change has the potential to lead to large regional hydroclimatic shifts -in the 279 case of Southern Africa towards more drought -prone conditions 35,37-39 . Our scenario is not a 280 deterministic projection, but rather a storyline (or scenario-based) evaluation seeking to 281 identify aspects that are critical in responding to future drought events. However, it allows to 282 us to conclude that more optimistic scenarios are only possible if multiple dimensions of 283 urban inequalities are addressed before the next Day Zero, whilst also abandoning the 284 assumption that future droughts will be similar in scale to those experienced in the past.  There are a number of regions which have historically been drought-prone and that are 481 projected to become "drought hotspots" under future climates 56 . In the context of our 482 impacts-based focus on urban droughts, an additional relevant criterion was to identify large 483 urban areas vulnerable to water scarcity, and affected by unequal access to water. Southern 484 Africa represents a "perfect storm" coincidence between these different aspects, being a 485 region currently subject to droughts, projected to experience more severe droughts in the 486 future (see "Maputo is likely to face unprecedented droughts") and having rapidly growing 487 urban agglomerates characterised by large socio-economic inequalities. Cape Town is a 488 natural choice for Pillar 4, having been widely reported as the first major city to be near the 489 "day zero" no-water scenario 57 . Maputo, on the other hand, has experienced severe droughts 490 in the recent past, but in comparison has received scant attention by the media and scientific 491 community. However, it shares Cape Town's vulnerability to water scarcity, large 492 inequalities, a segregated urban form, and additionally has unevenly developed water supply 493 infrastructure 43,58,59 . As such, it is a highly relevant case study on which to build a socio- in response to the water shortage affected lower income residents significantly more than 546 affluent ones (see also Pillar 1 and 4). Neighborhoods at the margins of the water supply 547 network experienced much longer and intense shortages than those centrally located. Some 548 only received water twice a week, others experienced water shortages for over three weeks, 549 and some only had water at night. Despite this, residents continued to be billed and charged 550 for regular water consumption, and threatened disconnection in case of non-payment. The drought is exemplary of the uneven impact of reduced water availability across intra-urban 552 spaces. With increased water shortages, storage facilities became the most essential coping 553 strategy. Whilst higher income residents could rely on a higher storage capacity (500 to 1500 554 L) to cope with water rationing measures, mid and low-income neighborhoods had to make 555 due with 200-250 L to 1.5 L containers. Additionally, affluent households that were already 556 less affected by water rationing measures were able to integrate their supply with private 557 wells, boreholes and bottled water. 558 Third, water shortages in low income areas generated or exacerbated existing gendered and 559 well-being inequalities. Women in charge of water-intense domestic chores (cleaning, 560 cooking, doing laundry) had to fetch water from boreholes or better served neighborhoods. 561 As a result, they often missed work or had to wake up at night to do laundry and store some 562 water for the day. These coping practices increase women's water labour and stress, as well 563 as everyday risks of violence for women having to collect water at night 66 . Last, the drought 564 also had several negative health implications, especially for low-income dwellers. There is a 565 strong correlation between urban poverty and the use of on-site sanitation. Today, approximately 64% of the population is connected to the centralized water supply 587 network. The drought, however, has shown that coverage does not always entail access: 588 increased coverage resulted in reduced availability as the Corumana Dam project to increase 589 supply was not completed before the drought. Moreover, water shortages exacerbated 590 inequalities embedded in the technical characteristics of the network and in the spatial 591 distribution of reservoirs. As noted for other postcolonial cities (Pillar 1), the network in 592 Maputo prioritizes the city center by design. The distribution centers are concentrated in the 593 proximity of the city center and, in times of water rationing, water distributed from the center 594 to the periphery, was mostly consumed by higher income neighborhoods, who also relied on 595 larger storage facilities 43 . 596 Transformative potential 597 As suggested in Pillar 1 and 4, the drought turned into a market opportunity for existing and 598 emerging profit-oriented providers. SSIPs were able to increase their market share, with 599 many households connected to the water utility and located in proximity to private systems, 600 opted for a second connection to augment supply. Other profit-oriented initiatives included water resale from boreholes or better served in-house connection, and water tankers. 602 Moreover, in 2021 the Ministry of Infrastructures announced an effort to create the conditions 603 for greater private sector participation in water service provision in Greater Maputo 70 . This 604 initiative is linked to the overall strategy of the government in response to the drought, which 605 is largely prioritized incrementing supplies over water conservation. 606 Water conservation measures were limited to public campaigns on how to save water (e.g. 607 avoid using drinking water to clean, water lawns and washing cars, using buckets rather than 608 showers) rather than sanctioned restrictions. In contrast, incrementing water supplies was and 609 remains the main short-and long-term strategy. This strategy was promoted by discursively 610 framing the drought as natural and water shortages as a problem to be addressed by overconsumption fines and installation of metering devices to enforce compliance-affected Affluent households that were used to consuming up to 8560 liters per day, had to 650 significantly reduce their consumption and give up irrigating lawns, washing cars and filling 651 their swimming pools, Yet, they did not suffer from shortages. These households were largely 652 unaffected by the tariff increases and fines, and were able to access or quickly resort to 653 alternative water sources, such as bottled water, rainwater and groundwater, and substantially 654 increase their water availability. Conversely, the same restrictions are described as "a shock" 655 by townships residents and working-class households who could not afford the increases in 656 tariff, the fines nor the costs of accessing or developing alternative water sources. Moreover, 657 in low-income areas it is common for more than one household to share one housing unit. 658 These housing units, therefore, had to share the allocated 350 liters among up to 15 people. 659 Last, low-income we most of the metering devices that halted the consumption of water at 660 350 liters/unit/day, were installed in lower-income households 8,71,72 . Many women living in 661 these areas faced a considerable amount of stress every time the metering device interrupted 662 the water provision in the middle of the day. Without relying on any alternative, these women 663 had to give up on washing their clothes, cleaning the house or cooking the family meal 8 . 664 Uneven water insecurity levels across intra-urban spaces and socio-technical measures 665 enforced by the municipality generated different recovery trajectories across the city. In low-666 income neighborhoods, many households continue to struggle in the aftermath of the drought, 667 due to the increased water tariffs and the rationing imposed through water metering devices. 668 Conversely, higher income residents enhanced their resilience to future droughts by investing 669 in alternative water sources. In fact, the reduction of the City's water demand from 1000 to 670 500 Million Liters per/day is attributable to larger consumers going off the grid rather than to 671 actual reductions in consumption 73 .

HH Responses and Intersectionality
Water shortages have a cascading effect on other urban inequalities (health, safety, food security) Water shortages have a cascading effect on gender inequalities Water rationing and demand management measures exacerbate inequalities in access to water

THEORETICAL EXPLANATIONS
Vulnerability mediates the impacts of the drought on different social groups and individuals Vulnerability differs across intra-urban spaces, identities (e.g. gender, race), and income groups Vulnerability is tied to the levels of water (in)security experienced before the event Water (in)security is also experienced by residents connected to the centralised water supply network

THEORETICAL EXPLANATIONS
Uneven, exclusionary development trajectories determine unequal impacts of the drought Colonial segregation, racial capitalism, patriarchy shape uneven drought impacts Water (in)security is generated by investment priorities, housing policies, market-based water pricing regimes Producing Scarcity Droughts are framed as a natural and unpredictable, deflecting attention from political responsibility Framing nature as the problem generates consent for unlimited infrastructure development and consumption Demand management measures can pave the way to managerial approaches and privatization of water utilities Drought generates new coalitions and trigger multiple moral claims on water beyond its economic value Droughts are generated by combined physical and human-produced water scarcity Development-oriented interests, politicians and water providers might profit or politically benefit from droughts Market-based reforms have increased vulnerability to droughts Water (in)security is also generated by overconsumption of water by elite users

THEORETICAL EXPLANATIONS
Social pressure is exerted on overconsuming users to reduce their use during droughts

HH Responses and Intersectionality
Water shortages have a cascading effect on other urban inequalities (health, safety, food security) Water shortages have a cascading effect on gender inequalities Water rationing and demand management measures exacerbate inequalities in access to water

THEORETICAL EXPLANATIONS
Vulnerability mediates the impacts of the drought on different social groups and individuals Vulnerability differs across intra-urban spaces, identities (e.g. gender, race), and income groups Vulnerability is tied to the levels of water (in)security experienced before the event Water (in)security is also experienced by residents connected to the centralised water supply network

THEORETICAL EXPLANATIONS
Uneven, exclusionary development trajectories determine unequal impacts of the drought Colonial segregation, racial capitalism, patriarchy shape uneven drought impacts Water (in)security is generated by investment priorities, housing policies, market-based water pricing regimes Producing Scarcity Droughts are framed as a natural and unpredictable, deflecting attention from political responsibility Framing nature as the problem generates consent for unlimited infrastructure development and consumption Demand management measures can pave the way to managerial approaches and privatization of water utilities Drought generates new coalitions and trigger multiple moral claims on water beyond its economic value Droughts are generated by combined physical and human-produced water scarcity Development-oriented interests, politicians and water providers might profit or politically benefit from droughts Market-based reforms have increased vulnerability to droughts Water (in)security is also generated by overconsumption of water by elite users

THEORETICAL EXPLANATIONS
Social pressure is exerted on overconsuming users to reduce their use during droughts