Effects of population growth on Israel's demand for desalinated water

Israel has long faced chronic water scarcity, historically managed through technological innovation, conservation, wastewater recycling, and policy measures. Despite these efforts, natural sources like the Sea of Galilee often reached critically low levels, prompting a national shift toward seawater desalination starting in 2005. As of 2020, desalination supplies about 50% of domestic needs. However, Israel’s exceptionally high population growth (averaging just over 2.1% annually over the past 30 years) is projected to raise total population from ~9.5 million (2022) to 15–25 million by 2065. This study evaluates how three population growth scenarios (high: >2% annually, medium: tapering to 1.6%, low: tapering to 0.8% by 2065) will affect water demand and supply from 2020 to 2065. Using historical stability in per-capita consumption, the research posits that demand will scale with population. The purpose is to quantify future desalination needs, energy implications, wastewater production, and the relative role of climate change vs. population growth. The study’s importance lies in planning infrastructure and policy to ensure reliable supply under accelerating demographic pressures, with broader relevance to other water-scarce, fast-growing regions.

The study projects Israel’s water demand and supply mix from 2020 to 2065 using demographic scenarios and historical consumption data. Population scenarios are sourced from Israel’s Central Bureau of Statistics: high-growth maintains >2% annual growth; medium-growth reduces to 1.6% by 2065; low-growth reduces to 0.8% by 2065. Historical data (1992–2020) indicate stable per-capita consumption, enabling demand modeling primarily as a function of population. Between 2010–2020, total water consumption averaged 246 m³ per capita annually, with domestic consumption averaging 100 m³ per capita annually. The model assumes these per-capita consumption values remain constant through 2065, consistent with Israel’s Master Plan for the National Water Sector. Natural water supply assumptions: Israel’s extraction from natural sources (Sea of Galilee, aquifers, surface water) has declined due to sustainability limits and environmental considerations. The model assumes a 20% decline in natural water production by 2065 relative to the long-term mean of 1.23 billion m³ per year, reflecting climate-change impacts and policy constraints on sustainable yields and ecological allocations. Wastewater assumptions: Israel captured and treated about 60% of domestically consumed water for agriculture during 2010–2020. The model maintains a 60% treated wastewater reuse rate for agriculture going forward, acknowledging environmental and regulatory constraints. Desalination capacity framing: For comparability, a desalination “unit” is defined as 100 million m³ per year, approximating the average annual output of existing Israeli plants circa 2020. Future desalination requirements are computed as the balancing component to meet total projected demand after accounting for constrained natural sources and projected treated wastewater volumes. Energy analysis: For contextual implications, the discussion evaluates electricity demand for reverse osmosis using 3 kWh/m³ as an efficiency benchmark for best-in-class plants. This electricity estimate excludes additional energy for intake pumping, distribution, and wastewater treatment. Sensitivity and context: The study discusses robustness under potential per-capita demand reductions (illustrative 30% decline) and contrasts population-driven impacts with those from climate change. Data and code are publicly available (Israel CBS; GitHub repository).

- Total water demand in 2065 is projected to reach: 3.8 billion m³ (low growth), 4.9 billion m³ (medium), and 6.2 billion m³ (high), up from ~2.4 billion m³ in 2020. Under high growth, demand increases by ~160% over 2020 within 35 years, quadrupling the historic growth rate (1960–2020). - Required desalination by 2065 rises from ~0.5 billion m³ in 2020 to: 1.9 (low; +280%), 2.75 (medium; +450%), and 3.75 billion m³ (high; +650%). - Desalination infrastructure scale by 2065 (100 MCM units): 19 (low), 27 (medium), 37 (high). Under high growth, 7 new units would be needed between 2020–2035 and 11 additional units between 2055–2065. - Treated wastewater production increases to: 0.9 (low), 1.2 (medium), and 1.5 billion m³ per year (high) by 2065, potentially exceeding agricultural absorption capacity. - Natural water becomes the smallest source (except possibly in the lowest growth case). Natural water per capita falls to <40 m³ (high), ~50 m³ (medium), and ~63 m³ (low) per year by 2065, from >300 m³/person/year before 2000. - Energy implications: At ~3 kWh/m³ for reverse osmosis, the high-growth desalination requirement implies an additional ~11 TWh/year electricity (about 15% of current national generation), excluding intake, distribution, and treatment energy. - Climate change impact is comparatively small: a 20% decline in natural sources by 2065 equates to ~245 MCM/year loss relative to 2020, an order of magnitude smaller than population-driven demand increases. - Even with a substantial 30% reduction in per-capita consumption, high-growth 2065 desalination needs would still be ~2.3 billion m³/year (+350% vs. 2020), requiring major infrastructure investment.

The findings indicate that population growth is the dominant force shaping Israel’s future water system, far outweighing climate-induced reductions in natural supply. Desalination will necessarily provide the bulk of additional water, but at significant environmental and energy costs. Meeting high-growth requirements could add ~11 TWh/year of electricity demand for reverse osmosis alone, with further energy needed for intake, conveyance, and treatment, likely increasing greenhouse gas emissions given the current fossil-heavy power mix. Siting additional coastal plants poses risks to coastal access and ecosystems, although long-term monitoring to date has not shown consequential damage; ongoing vigilance is needed. Health considerations arise from desalinated water’s low mineral content (e.g., magnesium), warranting remineralization strategies and health monitoring. Treated wastewater will expand, potentially outpacing agricultural demand due to agronomic constraints (salinity/sodicity risks, proximity restrictions to aquifers, crop limitations) and land-use changes reducing irrigable area. This raises infrastructure and policy challenges for effluent management, including the potential need for advanced treatment and potable reuse to offset desalination demand, reduce energy use and emissions, and alleviate coastal pressures. If reliance on treated effluent for irrigation is curtailed, Israel faces tradeoffs between costly desalinated water for agriculture and increased dependence on food imports with related security and sustainability implications. Security risks include vulnerability of coastal desalination assets to attacks and the stress of regional obligations and potential exports to Jordan and the Palestinian Authority. Cooperative wastewater treatment and pollution control in neighboring areas could benefit all parties. Ecologically, reduced natural flows and increased human demand may further strain ecosystems and recreational water access, necessitating dedicated environmental allocations. Overall, while technological improvements and aggressive efficiency can temper demand, they are insufficient to eliminate the need for large-scale desalination expansion under expected demographic trajectories. Israel’s experience serves as a bellwether for other water-scarce, rapidly growing regions, highlighting the critical coupling of water planning with energy decarbonization, land-use policy, and transboundary cooperation.

Israel’s rapidly growing population will require a substantial expansion of desalination capacity through 2065, with total demand scaling with population and natural sources contributing a diminishing share. Even under conservative assumptions and potential efficiency gains, desalination must increase several-fold, driving significant electricity demand and associated environmental tradeoffs. Treated wastewater volumes will grow and may exceed agricultural absorption capacity, necessitating strategic investments in advanced treatment, potable reuse, and revised allocation policies. The climate-change impact on water availability, though important, is small relative to the demographic driver in terms of supply-demand balance. Future research and policy should prioritize: integrating low-carbon energy with desalination; comprehensive assessments of health implications and remineralization strategies for desalinated water; long-term impacts of treated effluent on soils, crops, aquifers, and human health; the feasibility and design of potable reuse to reduce desalination dependence; coastal and inland siting tradeoffs and environmental safeguards; and regional cooperation mechanisms for wastewater treatment and transboundary water quality. Israel’s trajectory will provide key lessons for other regions facing similar water-energy-population challenges.

- Demand modeling assumes stable per-capita total (246 m³/person/year) and domestic (100 m³/person/year) consumption through 2065; deviations from these values would alter projections. - Natural supply is represented by an aggregate 20% decline from a long-term mean (1.23 bcm/year) by 2065; actual climate impacts and policy allocations could differ spatially and temporally. - Energy estimates consider only reverse osmosis electricity (≈3 kWh/m³) and exclude intake, conveyance, distribution, and wastewater treatment energy. - Agricultural absorption of treated wastewater is treated via a fixed reuse rate (60% of domestic wastewater) and does not explicitly model crop mix, land-use change, regulatory constraints, or soil degradation dynamics. - Environmental, health, and ecological risks (e.g., coastal impacts, mineral deficiencies, contaminants of emerging concern) are discussed qualitatively rather than quantified. - Security risks and regional water-sharing obligations are acknowledged but not incorporated into the quantitative model. - Infrastructure unitization (100 MCM “units”) is a simplification; future plant sizes, efficiencies, and modularity may differ.