Expansion of desalination
While reliance on desalination may allow Israel to meet basic domestic and agricultural needs, doing so will have considerable environmental consequences. Foremost, increased production of desalinated water will lead to a correspondingly steep rise in energy demand. The world’s most efficient desalination facilities currently require 3–3.5 kWh to desalinate 1 m3 of seawater10,11,12. Assuming the lower end of this bound, under the high-growth scenario, Israel will need an additional 11 TWh per year, or about 15% of the country’s current electrical generation. For comparison’s sake, this amount of electricity would require the equivalent of a 1600 MW natural gas power plant operating with an 80% capacity factor. Of course, technological improvements can be expected to make the desalination process less energy intensive, but the rate of reduction is expected to be limited13. We emphasize that these numbers include only the electricity required for the reverse osmosis process. They do not include the cost or energy associated with pumping water from the Mediterranean, distribution within Israel, and eventual wastewater treatment, all of which are energy intensive in their own right14. While renewable energy generation holds great promise, it could take decades before Israel has a low-carbon electricity system. Indeed, Israeli pledges at the Glasgow COP 26 envision only 30% of electricity coming from renewable sources by 203015. Should Israel pursue a solar PV-based decarbonization strategy, it will require substantial amounts of open space, in a country that already suffers from land shortages12. If solar PV is to become a main source of electricity generation in Israel, then demand will far exceed what is viable to produce on rooftops. At present, Israel generates over 90% of its electricity from fossil fuels, mostly natural gas and in the near-term, desalination will lead to increased greenhouse gas emissions14.
The construction of new desalination facilities has the potential to negatively affect Israel’s coastal landscape and aquatic coastal ecosystem. At present, Israel’s major desalination plants are all located along the country’s Mediterranean shoreline, with the future Haifa and Sorek II plants also planned for the coast. Significant future construction has the potential to limit public access to coastal recreation areas. While the construction of future desalination facilities at inland locations may alleviate the environmental impact on Israel’s coast, the feasibility of such construction is still being evaluated. An inland approach could increase the energy requirements for desalination, since it would require pumping seawater further inland. Moreover, scientists and environmentalists have voiced concerns that increased reliance on the pumping of seawater and discharge of brine following desalination over the long term has the potential to damage Israel’s coastal ecosystems, including plant and animal life16,17,18. For almost two decades Israel’s Oceanic and Limnological Research Institute has carefully monitored the effects of desalination facilities in these areas and has yet to detect signs of consequential ecological damage19,20. Notwithstanding, this is an issue that requires continuous observation and analysis.
A transition to desalinated water as the primary source of drinking water also raises a number of potential health concerns. Notably, desalinated water is lacking in certain minerals, such as magnesium, considered essential for human health21,22. The long-term consequences of consuming water that does not contain these elements are unknown21,22.
Sustainability of treated wastewater for agriculture
Despite the boon that treated wastewater has been to Israeli farmers—ensuring a steady supply of low-cost water—leading voices within the scientific community have raised potential environmental and health concerns that question the sustainability of Israel’s practices23,24,25,26.
Treated wastewater, including Israel’s relatively high-quality effluents, remains high in salt content, which can lead to reduced plant yield and increase the risk of long-term soil degradation26,27,28. In particular, recent research has demonstrated that irrigation water with a high relative fraction of sodium can cause irreversible breakdowns in soil structure, such that the affected land can no longer support agricultural production. Long-term use of saline water also has the potential to pollute Israel’s aquifers27.
Treated wastewater is additionally known to contain various chemical compounds—ranging from pharmaceuticals to heavy metals—that may present risks to human health. When used for agriculture, pharmaceuticals and heavy metal compounds can be taken up by food crops and consumed by people29,30,31,32. Crucially, the health consequences of long-term exposure to these compounds are uncertain and further research in this area is needed33.
Should Israel determine that reliance on treated wastewater for agriculture is too great a liability, this would create a twofold stress for the country’s water infrastructure. First, additional water supplies would be required to sustain the country’s farmers, with the only viable alternative likely being the production of additional desalinated water. Given current energy prices, however, the cost of using desalinated water appears to be prohibitively expensive for most crops25,34. Israel would then face a choice between continuing to support local agricultural production, despite the high costs, or moving to import required food supplies, which could be expensive and present potential national security risks. Second, Israel would have to find an environmentally acceptable method of discharging the large quantities of wastewater previously allocated to agriculture. If reusing treated effluent for agriculture is no longer viable, Israel will need to adjust its water treatment infrastructure.
One plausible scenario for coping with increased quantities of domestic wastewater is the possibility of treating this water to a higher level so that it can be re-used as drinking water, as has been done in potable reuse programs for years in American states like California, Virginia, and Colorado35. Expanded potable reuse could also lead to a decrease in Israel’s demand for desalinated water, lowering energy costs and greenhouse gas emissions while ameliorating pressure on Israel’s coastal landscape and ecosystems. Treating wastewater to a higher level could also enable continued use by farmers, albeit at a higher cost.
Effect of climate change minimal compared to population rise
Our analysis shows that the expected effects of climate change on Israel’s water supply are likely to be minimal compared to those of population growth. An assumed 20% decline in production from natural water resources by 2065 (“Methods””), represents a decrease of 245 million m3 per year in comparison to 2020 levels. Even if we consider a larger decline in natural sources due to climate change, the lost capacity pales in comparison to the increased demand from population growth, which is an order of magnitude larger. That is, our projections show that Israel’s water supply will remain precarious even if the worst consequences of global climate change do not materialize. Of course, even if climate change’s effects on Israel’s drinking water may be small compared to that caused by population growth, any change in precipitation patterns also has the potential to raise the risk of forest fires, cause increased flooding, and affect the region’s wildlife.
Security concerns and regional cooperation
In past military conflicts, Israel’s coastal desalination facilities have been a target for both rocket and cyber-attacks. Thus far, Israel’s Iron Dome and other defense systems have withstood these challenges. Nonetheless, should a desalination plant be forced offline for a prolonged period of time, it could potentially disrupt water supply.
It is also important to note Israel’s obligations to provide fixed quantities of water to the Palestinian Authority and Jordan, pursuant to the Oslo II Accords and the 1994 peace treaty with Jordan. While it is beyond the scope of this analysis, Israel’s neighbors are themselves under intense pressure to meet the water demands of growing populations. Unlike Israel, Palestine and Jordan are already suffering from major deficits in supply, with access severely limited. Moreover, Israel’s neighbors are less well positioned to increase desalination capacity. Water scarcity in Jordan, Palestine, and other countries in the region has the potential to cause significant unrest, representing a major security concern for Israel and its neighbors. The possibility of Israel supplying desalinated water to its neighbors has often been suggested as a possible component of regional peace building36. In fact, in 2021 Israel agreed to double its annual water supply to Jordan to 100 MCM37. Any additional steps to the export of water to Jordan or Palestine would, however, add an additional component of stress to an Israeli water system that will already be facing unprecedented demand driven by population growth.
The sustainability of any future plan to address Israeli water scarcity could be bolstered by steps to increase cooperation between Israel and its neighbors. At present, for example, significant quantities of untreated wastewater flow from the West Bank into Israel38,39,40. Likewise, sewage discharge from Gaza into the Mediterranean has in the past caused fouling of membranes at Israel’s Ashkelon desalination plant, even forcing the plant to go offline41. Capture and treatment of wastewater within Palestine would have the dual benefit of increasing potential irrigation supplies for Palestinian farmers while reducing pollution of transboundary water resources42. Increased water access, of course, also has the potential to decrease water-driven security risks in the region.
Ecological concerns
The projections presented here only consider how an increase in water demand could impact future demand from desalination. We do not examine how rising population levels might limit access to water resources for recreational purposes. Nonetheless, we can expect that a larger population will put increased strain on access to Israel’s streams, rivers, and lakes43. Likewise, reduced natural flows are liable to stress the flora and fauna in the country’s national parks and nature reserves43. A recent report by Israel’s State Comptroller revealed that the country’s compliance with the UN Convention on Biodiversity is woefully inadequate, with the country failing to meet 74% of the convention’s measurable objectives44. Providing nature with reliable and reasonable water flows will be critical to preserving the country’s unique ecosystems, but increasingly difficult given the anticipated growth in anthropogenic demands.
Technological Improvements
The trends discussed here are robust even if dramatic technological improvements allow Israel to greatly reduce per capita water consumption. For instance, if we assume a 30% decline in per capita consumption, a truly dramatic change considering historical values and Israel’s already impressive water conservation practices (Methods), Israel would still need to produce 2.3 billion m3 of desalinated water in 2065 for the high-growth scenario. This constitutes a 350% increase in capacity compared to 2020 levels and would require significant infrastructure investment.
Global Bellwether
The extent to which Israel is able to meet the water demands of a growing population in the face of increasingly insufficient natural supplies could provide valuable insight for regions and governments facing similar pressures. The population growth rate in the American Southwest, for instance, has far outpaced that of the U.S. as a whole, with water resources in the region already extremely stressed. In contrast to Israel, the American Southwest lacks the advantages of a centralized water authority. Additionally, many of the population centers in the American Southwest are far removed from potential sources of desalinated water, making the challenge of water delivery even greater and the value of efficiency and wastewater treatment and reuse higher. Likewise, middle-income countries facing acute water scarcity (e.g., Brazil, South Africa) may look to Israel’s experience as they seek to increase water supplies for growing populations.
Hydrological stability is typically considered a prerequisite for sustainability. In water-scarce regions, projected climate change-driven precipitation decreases matter. But the anticipated shortages caused by population growth appear to matter far more. Desalination offers a possible way-out of such conundrums. But for the foreseeable future, the absence of low-carbon electricity to power this energy-intensive process means that relying on desalination technology will contribute to increased greenhouse gas emissions. Should Israel struggle in its effort to meet growing water demand, or be unable to do so without significantly increasing carbon emissions, it will provide a stark warning of the challenges ahead.
Water in the context of other constraints on israeli population growth
While many technologically-optimistic managers perceive desalination as a panacea for providing water supply under conditions of steady population growth, in other areas of life, solutions are more elusive. This is particularly true in designing infrastructure that utilizes land resources, such as housing, agriculture, and the production of raw materials for construction.
To meet projected demand for residential housing between 2020–2030, Israel will need to add an additional 560,000 housing units to present stock. Due to the nature of exponential growth functions, however, demand will grow to over 1.05 million housing units between 2050–2060. Supplying the corresponding housing and infrastructure is expected to put further pressure on Israel’s open spaces, which are already disappearing at a rate of 30 km2 a year8. The depletion of open spaces, including agricultural lands, could also pose a threat to Israel’s food security in the future. Already, official figures cite current Israeli food imports at around 64% of total calories consumed by the population45 with some experts calculating even greater dependence on food imports46. Besides expanding the carbon footprint of Israel’s food supply, such significant reliance on imported crops increases the country’s vulnerability and exposure to global shocks in the food markets during times of international turbulence or military conflict.
Source: Resources - nature.com
