“Fresh drinking water is an issue of primary importance, since it is indispensable for human life and for supporting terrestrial and aquatic ecosystems. Sources of fresh water are necessary for health care, agriculture and industry. Water supplies used to be relatively constant, but now in many places demand exceeds the sustainable supply, with dramatic consequences in the short and long term. Large cities dependent on significant supplies of water have experienced periods of shortage, and at critical moments these have not always been administered with sufficient oversight and impartiality. Water poverty especially affects Africa where large sectors of the population have no access to safe drinking water or experience droughts which impede agricultural production. Some countries have areas rich in water while others endure drastic scarcity … the deterioration of the environment and of society affects the most vulnerable people on the planet.”
Pope Francis, On Care for Our Common Home
“Water is the lifeblood of humanity. It is vital for survival itself and supports the health, resilience, development and prosperity of people and planet alike. But humanity is blindly traveling a dangerous path. Vampiric overconsumption and overdevelopment, unsustainable water use, pollution and unchecked global warming are draining humanity’s lifeblood, drop by drop. The effects are all around us – from climate change-driven heatwaves, droughts, floods and violent storms, to the world’s supply of fresh water being contaminated by pollutants, chemicals and torrents of salt water from rising seas.”
António Guterres, Secretary General of the United Nations, 2023 UN World Water Development Report
1. Introduction
“Water is life” declared Dr. Narain in her Water Session talk, as water is essential for humans and ecosystems to thrive. To meet human needs, presently irrigation accounts for approximately 70% of total global water withdrawals, followed by industrial use at 18% and municipal use at 12% (United Nations, 2023). The report also notes that there exist important regional differences in water use; e.g. in South Asia, the amounts are 91% for irrigation, 2% for industrial, and 7% for municipal. Instream uses support hydropower production, recreation, thermal and nuclear power plant cooling, and provide flows for shipping and ecosystems. Caretta et al. (2022) reports that probably approximately 50% of the global population now experience severe water scarcity at least part of the year and, at the opposite end of the spectrum, 44% of all disasters since 1970 are flood related. More ecosystem degradation and water-related disease outbreaks are now also occurring (Caretta et al., 2022). Populations that are vulnerable due to gender, income, age, being indigenous are and will continue to be the most impacted (Caretta et al., 2022).
Figure 1 shows the Global Water Security Index, which combines indicators of freshwater availability, water services, water management, water quality, and flood risk (Caretta et al., 2022). As can be seen, with the exception of parts of South America, there is considerably less water security in the Global South than elsewhere. With global water demand projected to increase by 20-30% by 2050 (Caretta et al., 2022) and with climate change increasing the frequencies of floods and droughts, water security will decrease unless management actions are taken.
The papers from the Water Session provided detailed evidence of these water challenges in the Global South and elsewhere. For examples, Dr. Narain reported that extreme precipitation has increased significantly in parts of India and this and other climate changes in some cases are causing migration; Dr. Kimutai noted that due to local increases in precipitation, lake levels have permanently risen in the Rift Valley Lakes in Kenya destroying some livelihoods; Dr. Strzepek pointed out the challenges smallholder farmers in Southern Africa, who regionally produce the most food, face because of increasing droughts and subsequent decreases in yields; Dr. Yu described the increased global failures of urban drainage networks that rely upon traditional gray infrastructure; and Dr. Muhinda discussed how climate change has contributed to ecological degradation of agricultural land through hillside soil erosion, landslides and recurrent floods.
Thus, there is an urgency to increase the resilience of our water resources to not only current challenges, but also to the new, uncertain threats from climate change. This synthesis paper reviews some of the common themes of the session’s papers and other sources on water-related challenges and management strategies relevant to the Global South. Before this is presented, however, at least two of the threats not covered in this session must be summarized.
Much of the world’s population, economic activities and critical infrastructure are concentrated in the coastal zone, with 41% of the global population living within 100 km of the shoreline (Martinez et al., 2007). Additionally, coastal ports provide critical pathways to transport materials into the interior of a region. These areas are particularly vulnerable: they are affected by compound disasters from both the land and the sea. In addition, sea level rise impacts freshwater resources by salt water intrusion into groundwater, increasing salinity in estuaries, and impeding urban drainage into oceans.
Another additional threat is the reduction in the extent of inland glaciers in the Andes and Central Asia as mentioned by Dr. Narain. These will result in significant declines in streamflows that could affect agriculture, industrial production, and municipal supply. By mid-21 century, these impacts may be felt by 1.5 billion people (Caretta et al., 2022)
2. Cross-Cutting Stresses
The first cross-cutting theme from the Water Session is that while reducing greenhouse gases is top priority, it is too late to reverse the impacts of climate change and transformative adaptation is thus urgently needed.
All the session’s papers noted that the causes of present and future water stresses are due to both hydrologic conditions as well as socio-economic conditions. For examples, Dr. Kimutai and Dr. Muhinda describe how land use and settlement patterns result in flood losses, not just extreme flows. Dr. Strzepek notes that drought impacts occur due to both demand and supply conditions.
Another common thread addressed by all the speakers is that the Global South is suffering the most under climate change while generally contributing the least to global emissions – an instance of environmental injustice; “the ultimate immorality” as stated by Dr. Narain. Additionally, the Global South encompasses pockets of impoverished and marginalized people with low adaptive capacity and weak institutions, high population growth rates, and sometimes civil unrest. Therefore, these regions face both excess burdens from climate change and limited capacity to adapt to their effects. For example, as Dr. Strzepek notes, globally smallholder farmers (84% of farms globally) will suffer the most from drought as they have high sensitivity to rainfall and low adaptive capacity. These overlapping challenges illustrate how improving adaptive capacity in the Global South must be a priority.
Another theme is that many regions of the world suffer from multiple water threats, not just a single threat. For example, large parts of West Africa, South Asia and other regions suffer from both floods and droughts, have large coastal zones, are heavily populated by cities with limited water infrastructure, and are highly dependent upon rain-fed agriculture. Dr. Kimutai pointed out that flood impacts in Kenya’s Rift Valley Lakes were exacerbated by recurring droughts. Beside economic losses, the counties of the Global South face cultural and biodiversity losses and public health impacts from all types of disasters. Therefore, the management of one water challenge cannot be looked at in isolation from the others, or from the social, cultural, and political systems in which they are embedded. Out-migration and displacement from water-scarce or flooded regions are occurring to escape these climate threats. In addition, many of the river basins facing risks from climate change are transboundary – requiring extensive negotiation and governance regimes for sustainable management.
In fact, related to the above, many nations not only face threats to water resources, but also to air quality, food, energy, and others and these threats are all inter-related and need to operate in unison, e.g. the Food-Energy-Water Nexus (e.g., see D’Odorico et al., 2018). Therefore, these challenges must also be cross-sectionally managed, the growing field of Multi-Sector Dynamics (https://multisectordynamics.org/). As an example, Dr. Muhinda related agricultural challenges to not only water management, but also to land use.
Another common thread is that many nations of the Global South are challenged to meet the targets of Sustainable Development Goal (SDG) 6 – “Ensure Availability and Sustainable Management of Water and Sanitation for All.” Presently, two billion people are without safe drinking water and 3.6 billion are without safe sanitation (United Nations, 2023). Other SDG 6 targets include reducing water pollution, increasing water reuse, increasing water-use efficiency, implementing integrated water resources management (IWRM) and transboundary cooperation, restoring and protecting ecosystems, supporting the Global South in expanding capacity building, and strengthening participation of local communities in water management. The Global Water Partnership (2009) defines IWRM as a “process that promotes the coordinated development and management of water, land, and related resources in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems.” IWRM is carried out in the social, cultural, and political systems in which a water system is embedded. SDG 6 is closely related to all the other Goals, for examples, poverty reduction, hunger, health, education, justice, energy, livelihoods, and cities. Climate change threatens the ability to achieve any of the SDGs.
Given the increase in climate risk and the highly interconnected nature of water systems, there is the need for rapid adaptation of water resources to climate change. A review of a few water-related adaptation concepts suggested at the Summit and elsewhere follow. The end result must be affordable water for all (Dr. Narain).
3. Cross-cutting Solutions
An initial action is to implement holistic water security planning throughout the Global South. Water security is “the availability of an acceptable quantity and quality of water for health, livelihoods, ecosystems and production, coupled with an acceptable level of water related risks to people, environments and economies” (Gray and Sadoff, 2007). World Bank (2018) reports that UN-Water expanded this to “the capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well-being, and socio-economic development, for ensuring protection against waterborne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability.” For SDG 6, UN-Water (2020) emphasizes this could be achieved by accelerating 1) Financing; 2) Data and information; 3) Capacity development; 4) Innovation; and 5) Governance. The importance of good governance cannot be overlooked. Dr. Muhinda noted that the success of the ecosystem restoration program in Rwanda was partly due to strong governance. In general, “the objective should be to simultaneously balance economics, societal well-being, and sustainability – acknowledging that no one of them can be achieved if one is dropped” (personal communication, Jonathan Lamontagne).
Nature-Based Solutions (NBS) present an alternative to traditional grey approaches and can possibly manage many of the compound climate threats to water systems. NBS are engineered systems that mimic some aspects of natural systems and they are supported by a growing field of research and practice. In addition, they have important social and environmental co-benefits. For example, Sponge Cities mentioned by Dr. Yu in this session not only help manage urban flooding but also provide groundwater recharge for water supply, create habitat, provide recreation, counter urban heat island effect, and store carbon. Several of the speakers recognized that such effective approaches are based upon valuable indigenous knowledge.
Associated with NBS are other low technology, decentralized, democratic approaches to water management that need to be expanded – many based upon indigenous knowledge. For example, these strategies include the small reservoir storage systems in the Sahel-Sudan and Sri Lanka, regenerative agriculture, water conservation and floodplain management, and preservation of wetlands and marshes. Widely cited low-tech approaches for improving agricultural productivity also include access to markets and services, safety nets, increased agricultural research, information and credit availability, and the adoption of farming practices that improve climatic resilience.
At the other end of the spectrum are options for advanced technology in water management, with specific attention to multi-sectoral design avoiding the past approaches of viewing water in isolation. Much of this can be implemented while rebuilding from natural and human related disasters or in areas with existing minimal services with the goal of leapfrogging over, as Dr. Narain pointed out, some of the past single sector, silo-based approaches. In a fully connected system, water management is considered a circular system with no water seen as waste and the outputs from one sector are re-cycled or re-used in another. In an urban area this is referred to as Integrated Urban Water Management (IUWM), which is the holistic management of urban water supply, sanitation, stormwater, and wastewater to achieve sustainable economic, social and environmental objectives. All parts of the urban water cycle are managed together instead of separately. There are already a few global examples of direct potable re-use which not only solves the water supply problem but also the wastewater problem. Safely capturing the water, heat and nutrients in urban wastewater for use in other sectors is also possible as Dr. Narain and others also emphasized. The overall goal is “reduce, remove, reuse, recycle” (Carretta et al. 2023). Using sensors, monitoring technology, weather forecasting and advanced management algorithms can to lead “intelligent” water management with significant cost savings and efficiency in all water sectors, particularly in cities and agriculture (e.g. see Kerkez et al., 2016). Machine learning to unravel complex data sets and/or replace or augment traditional process based hydrologic and hydraulic models is also feasible (Ghobadi and Kang, 2023). For example, Tulbure et al. (2022) used machine learning algorithms combined with remote sensing, another available advanced tool, to generate historic surface water flooding.
Dr. Kimutai and others stated transformative funding is also urgently needed. For example, the World Bank estimates that funding to meet water supply and sanitation goals in the Global South need to increase by 200-300% annually (https://www.worldbank.org/en/topic/water/publication/funding-a-water-secure-future).
In regards to the adaptation planning process, advanced algorithms for decision making under the deep uncertainty of climate change are being integrated with participatory planning methods within the frameworks of IWRM and Multi-Sector Dynamics to develop innovative and equitable adaptation strategies to climate changes using adaptive management (e.g., see Marchu et al., 2019).
4. Summary
Climate change presents threats to water systems that unequally impacts the Global South, indicating the pressing need for effective and thoughtful adaptation. Water systems are highly connected to each other and to other sectors such as health, and we must design our adaptations to reflect that and the societal, cultural, and political contexts in which they exist. Approaches for adaptation should be guided by holistic, participatory planning and designed to simultaneously bolster resiliency in multiple systems against many threats using a variety of appropriate approaches. More research is needed on all aspects of water management to hasten the transformative changes needed.
Acknowledgements
The author appreciates the review comments on an earlier version of this paper of Catherine Knox, Jonathan Lamontagne, Patrick Ray, and Joel Smith.
References
Caretta, M.A., A. Mukherji, M. Arfanuzzaman, R.A. Betts, A. Gelfan, Y. Hirabayashi, T.K. Lissner, J. Liu, E. Lopez Gunn,R. Morgan, S. Mwanga, and S. Supratid. 2022: Water. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Portner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegria, M. Craig, S. Langsdorf, S. Loschke,V. Moller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 551-712, doi:10.1017/9781009325844.006.
D’Odorico, P., K. Davis, L. Rosa, J. Carr, D. Chiarelli, J. Dell’Angelo, et al. 2018. The global food-energy-water nexus. Reviews of Geophysics, 56, 456-531.
Ghobadi, F., D. Kang. 2023. Application of Machine Learning in Water Resources Management: A Systematic Literature Review. Water 2023, 15, 620.
Global Water Partnership and the International Network of Basin Organizations. 2009. A Handbook for Integrated Water Resources Management in Basins, Stockholm and Paris.
Grey, D., and C. Sadoff. 2007. Sink or Swim? Water Security for Growth and Development. Water Policy 9 (6): 545-71.
Kerkez, B., C. Gruden, M. Lewis, L. Montestruque, M. Quigley, B. Wong, A. Bedig, R. Kertesz, T. Braun, O. Cadwalader, A. Poresky, and C. Pak. 2016. Smarter Stormwater Systems, Environmental Science and Technology, 50, pgs 7267-7273.
Marchu, V., W. Walker, P. Bloemen, S. Popper (editors). 2019. Decision-Making under Deep Uncertainty, from Theory to Practice, Springer.
Martinez, M., A. Intralawan, G. Vazquez., O. Perez-Maqueo, P. Sutton and R. Landgrave. 2007. The Coasts of Our World: Ecological, Economic, and Social Importance, Ecological Economics, 63, 254-272.
Tulbure, M., M. Broich, V. Perin, M. Gaines, et al. 2022. Can we detect more ephemeral floods with higher density harmonized Landsat Sentinel 2 data compared to Landsat 8 alone? ISPRS Journal of Photogrammetry and Remote Sensing, 185, 232-246.
United Nations, The United Nations World Water Development Report 2023. 2023. Partnerships and Cooperation for Water. UNESCO, Paris.
UN-Water, 2020. The Sustainable Development Goal 6 Global Acceleration Framework. Geneva Switzerland.
World Bank. 2018. Beyond Scarcity: Water Security in the Middle East and North Africa. MENA Development Series. World Bank, Washington, DC.