Author: Willem Ligtvoet
Dossier: Water als prioriteit op de internationale agenda
Editor: Vincent van den Bergen en Willem Ligtvoet
Water security and adaptation to climate change is a matter of life and death for communities of deltas, coasts and islands and it is of paramount importance to prevent social and economic disruption and large-scale displacement of people. Will the new UN System-wide Strategy on Water and Sanitation make the change?
Deltas and Coasts face increasing water challenges
Today, approximately 2 billion people live in deltas, coastal zones and islands, many of which in large cities (figure 1). On the edge between land and sea, life is at the forefront of dealing with climate change, facing sea level rise, tropical storms, vulnerability of freshwater supply, and fluctuating river flows. While experiencing weather extremes beyond scientific expectations, these areas have to cope with further population growth and manage development. Many countries face a large adaptation gap, posing growing challenges with respect to flood safety and freshwater security. Climate change, population growth and economic development will continue and the coming decades – starting now – will be critical in bending the trend towards safer deltas, coasts and islands.
Figure 1 Delta and coastal communities are very vulnerable to the consequences of climate change, including accelerating sea level rise, and an increase of the intensity of tropical storms, variability in freshwater availability and extreme heat. Hundreds of millions of people live in fast growing cities. In many cities the rate of local subsidence, mainly due to groundwater abstraction, exceeds the actual rate of sea level rise and contributes to increasing flood risks and salinization. Source PBL 2023.
The UN System-wide Strategy on Water and Sanitation: a promising step?
Following the attention raised in the UN Water Conference in New York in 2023, the United Nations recently adopted a System-wide Strategy on Water and Sanitation and appointed for the first time a Special Envoy on Water, acknowledging after decades of neglect the pivotal role of water for development. This UN System-wide Strategy on Water creates the necessary environment and offers new opportunities for concrete steps towards the planned UN Water Conference 2026. Challenges lying ahead include i) still lacking global goals and targets (What do we want to achieve?) ii) insufficient coherency between relevant policy domains (water, climate mitigation and adaptation, biodiversity, agriculture, urban development) and iii) insufficient financial support for adequate water and adaptation policies. While the top 10% of the richest people in the world account for almost half of the global greenhouse-gas emissions (World Inequality Report 2022), low-income countries lack the financial means for adequate water infrastructure and adaptation. The UNEP 2023 Adaptation Gap report for instance shows that ten to eighteen times more money needs to be spent on reducing vulnerability to climate change than the rich countries currently raise in aid. This was about 21 billion dollars in 2021, but according to the UNEP study, an estimated 215 billion to 387 billion dollars should be available annually in the coming years.
| PBL 2023 study: from challenges to solutions in four hotspot landscapes Just before the start of the UN 2023 Water Conference of 24–27 March, in New York, PBL Netherlands Environmental Assessment Agency published The Geography of Future Water Challenges — Bending the Trend. Starting from a systems approach, this study explores solutions to reduce water- and climate-related risks across the world, up to 2070, accounting for a population growth towards 9 billion people and a climate change temperature increase close to 3° C. It assesses the effects of potential measures for four ‘hotspot landscapes’: River basins, Deltas and Coasts, Drylands, and Cities. Captured in infographics and focusing on High ambition pathways, this study shows that much can be achieved when following a transformative high-ambition approach. Major gains are a reduction of the impacts of new large hydropower dams; a structural reduction in water use in agriculture, households and industries; the provision of safe drinking water, hygiene and sanitation facilities for all, a reduction in flood risks and nutrient pollution of rivers and coastal seas; the prevention of further subsidence in deltas; the preservation of ecological quality of river systems; more crop per drop being produced in dryland regions due to improved water management and crop production; and a reduction of local and transboundary conflict risk. The strong improvements that can be achieved by 2070 under the High ambition pathway have many co-benefits for the Sustainable Development Goals (SDGs). These benefits are reflected in most regions but least of all in Sub-Saharan Africa, South Asia and Southeast Asia, where even higher levels of collective effort will be needed. The comprehensive study, rich in narratives and explorations, is complemented with a Policy Summary, which highlights the study’s main findings, offered in the context of the UN 2023 Water Conference. Specifically focusing on the global river and delta systems, PBL published the website Navigating Rivers and Deltas towards a Sustainable Future and the Deltas & Coasts short-read. |
Bending the trend in Deltas and Coasts is highly urgent
The major threats for deltas and coasts are well known and the PBL study The Geography of Future Water Challenges – Bending the trend (see Text box) gives a comprehensive overview, covering sea level rise, coastal and river flood risks, peak and low river discharges, freshwater supply, local subsidence and groundwater abstraction, sedimentation/erosion dynamics, and water pollution (nitrogen, phosphorus). The future flood risks, coastal erosion, and salinization of fresh ground- and surface water systems of the deltas and coasts will depend largely on the interaction between i) sediment input by rivers and the extraction by sand mining, ii) subsidence due to groundwater extraction (figure 1) and iii) the rate of sea level rise.
An assessment of future trends shows that for all important drivers the signs flag red under a Business-as-usual scenario (figure 2). The urgency for action is high: geological research reveals that most deltas were formed when sea level rise slowed down to 5-10 mm/year between 9,000 and 7,000 years ago, after a faster sea level rise at the beginning of the Holocene. This 5-10mm/year may be a critical range where the accretion of deltas can keep up with sea level rise. Given the projected rates of sea level rise by the IPCC towards 2100, this critical 5-10 mm/year range may be reached already within the next 50 years. Keeping the reduced sediment flows in many rivers and the local subsidence in mind, deltas and low-lying coastal areas will no longer be able to keep up with sea level rise through sedimentation processes and nature-based approaches. This will strongly increase the risk of displacement for millions of people. The remedy is investment in retaining and restoring as much as possible natural processes and/or build hard infrastructure to defend the areas.
Figure 2 Deltas, low-lying coastal zones and islands may face limits to adaptation. An assessment of the critical drivers and projected developments under a Business-as-usual scenario for deltas and coasts shows that many drivers flag red. A worrying situation, as both on the mitigation side (blue boxes) and adaptation side (grey boxes) there are hardly signs of adequate responses. The future situation will also depend on upstream developments (*). Source PBL 2023.
Towards a mission-based global strategy: ambition levels and pathways
The lack of general knowledge is not the main problem. What is lacking is sufficient internalization and overview at the global level, and clear goals and targets on regional, country and city levels. In contrast: with respect to mitigation, graphs are widely used, showing Business-as-usual developments, the global targets and the potential effect of different policy strategies. These graphs are being used to evaluate progress and check whether the reduction of green-house gasses on global and country level is on track. For water security and reducing climate risks, similar goals and graphs are still not available. Not withstanding the scientific difficulties, this should be pursued and the PBL study provides an interesting overview of graphs for relevant water and adaptation topics. In figure 3 examples are given for coastal flood risk and for emissions of nutrients to coastal seas. These kind of graphs, based on detailed pathways of solutions and regional breakdowns, should be developed as a basis for discussions about ambition levels for critical water challenges and climate adaptation.
Figure 3 Graphs showing what can be reached in deltas and coastal areas, depending on the level of ambition pathways of solutions relative to the Business-as-usual scenario (BAU). The High ambition pathway results in an enormous reduction of flood risks and nitrogen emission compared to the BAU. The red dots: what do we want to achieve? Source PBL 2023.
The importance of upstream-downstream interactions
Upstream-downstream interactions are highly relevant for effective policies in deltas and coasts on flood risks, water pollution, and retaining water and sediment flows (From source to sea approach). Today, for instance, an estimated 50-75% of the global sediment flows is trapped behind existing dams and more dams are expected to be built for hydropower production and water supply. And only a quarter of the total nitrogen load to coastal waters originates from within the deltas and coastal zones themselves; three quarters is coming from upstream. A structural reduction of nutrient loads to coastal waters requires efforts on the river basin scale.
The importance of transboundary governance of river systems in times of climate change is acknowledged within the EU, adopting the Guidance on River Basin Management in a Changing Climate early September this year. This guidance aims at integrating the climate adaptation challenges in transboundary river basin and water management addressing the projected impacts of increased heavy rainfall, prolonged droughts, heat waves, spread of invasive species and sea level rise. This is an important step. However, this is not the situation at the global level.
In August this year, India and Bangladesh were hit by an enormous flood disaster caused by abnormal and extremely heavy rainfall and affecting millions of people. The flooding in Bangladesh was probably exacerbated by the opening of a dam upstream in India, underlining the importance of transboundary collaboration and river basin approaches in protecting deltas.
The flooding of Bangladesh in August 2024 was probably exacerbated by the opening of an upstream dam in India, illustrating the importance of river basin approaches and transboundary collaboration.
Photo UNICEF https://news.un.org/en/story/2024/08/1153726
Water and climate adaptation critical for sustainable development
Water is linked to all Sustainable Development Goals (SDGs) and tackling the water and climate related risks is indispensable for bending the trend towards a climate-resilient and sustainable development. The PBL study shows that especially the High ambition pathway structurally reducing the water and climate risks in deltas and coastal areas, contributes in many ways to the SDGs, far more than is the case under a Business-as-usual Development (figure 4).
Figure 4. Comparing the projected contributions to the SDGs of improving water and climate adaptation policies in Deltas and Coasts, shows that the High ambition pathway (right), contributes far more to the SDGs (blue colors) than the Business-as-usual scenario (left). Essential for the High ambition pathway is an effective operationalization of SDG 16 (Strong institutions) and SDG 17 (Partnerships for the Goals). Source PBL 2023.
High urgency asks for a governance U-turn and global leadership
Deltas, coasts and islands deserve a mission-based global strategy. Flood safety, tropical storms and freshwater security are matters of life and death for coastal and delta communities and it is of paramount importance to prevent further social and economic disruption and large-scale displacement of people. The ongoing global water and climate change crises, and the unequal distribution of the global emissions as well as the climate impacts and risks across the world, show that current value systems, policies and economic practices are not fit to make the required changes.
In line with the conclusions of the Global Commission on the Economics of Water and many other studies, PBL states that a climate-resilient and sustainable development calls for urgent and fundamental shifts in governance approaches and priorities (figure 5). Needed are an explicit acknowledgement of the central role of water in sustainable development, innovative approaches and integration of policies across sectors and geographical scales, applying system-based spatial development strategies, developing new ways in how we measure success (‘From economic efficiency towards sustainable effectivity’ cf. figure 4), and improving global governance and scaling up funding for water and climate adaptation.
The urgency for dedicated action is high: climate change, population growth and economic development will not wait. The UN System-wide Strategy on Water and Sanitation and the upcoming UN 2026 Water Conference should provide an excellent opportunity for starting to build a participative mission-based strategy ‘from global to local’ for the deltas, coasts and islands, setting clear goals, challenging targets, and developing coherent plans and financing across the different regions. Based on such a process, international priorities can be determined in supporting the implementation of what where in the coming decades. Hopefully, global leadership the next years will prove to be a gamechanger in accelerating the highly required U-turn in governance and finance.
Figure 5. To bend the trend and structurally reduce the water- and climate-related risks across the world, asks for a U-turn in governance approaches and priorities from global to local and scaling up supporting financing. Source PBL 2023.
Drs Willem Ligtvoet
Independent advisor Water, Climate and Sustainable development and former Program Leader at the Netherlands Environmental Assessment Agency (PBL) for this field of work, on a global, European and national scale. WL was the initiator of The Geography of Future Water Challenges, the overarching PBL program 2016-2023 for the assessment of challenges and solutions (Bending the trend) as to the water and climate risks on a global scale. Trained as a systems ecologist (Leiden University), WL has worked as researcher at the National Institute for Nature Management and the University of Leiden (Mwanza, Tanzania), advisor at Witteveen+Bos (Netherlands, Indonesia, Egypt, Gaza) and as program leader at the PBL and its predecessors.