How Can Desalination Help Us Survive Water Scarcity?

Is desalination crucial in regions like East Africa and the Middle East, where droughts are becoming more frequent and freshwater supplies are diminishing, despite its reputation for being energy-intensive, costly, and environmentally harmful?

Throughout history, people have found various ways to make saltwater drinkable. Ancient Greek sailors would boil seawater, while the Romans used clay pipes to filter out the salt. This process, known as desalination, has a rich and long-standing tradition.

However, it is the modern advancements in desalination that hold the key to addressing water scarcity in the present and future. According to Manzoor Qadir, the deputy director of the United Nations University Institute for Water, Environment, and Health, these innovative techniques are crucial in tackling the challenges of limited water resources.

There is water all around, yet none of it is suitable for drinking

While water covers most of Earth’s surface, only a minuscule portion is safe for drinking. Less than 1% of the massive 326 million trillion gallons (1260 million trillion liters) of water on our planet is drinkable.

Unfortunately, these limited water resources are under increasing pressure. Factors such as rapid population growth, uneven distribution of freshwater, and worsening droughts due to climate change are causing water scarcity in many regions around the world.

A significant portion of the global population, about a quarter, resides in countries experiencing “extreme water stress.” This means that these places utilize at least 80% of their available water supply each year, putting them at risk of water shortages and prompting severe water use restrictions by authorities.

By the year 2050, even the most optimistic climate change scenarios project that an additional 1 billion people will face water scarcity.

The desalination industry is on the Rise

How Can Desalination Help Us Survive Water Scarcity

Desalination is an industry on the rise. Despite concerns about expenses, energy consumption, and environmental consequences, experts agree that desalination “is a growing industry.” It has been steadily expanding over the past two decades.

“The main driving force behind this growth is the increasing water scarcity,” explained Qadir. “More and more desalination plants are being built and put into operation.”

Currently, desalination plants actively use either thermal distillation, which heats the water and collects the vapor, or reverse osmosis, which filters water through a semi-permeable membrane as it is pushed through.

While there are alternative methods for obtaining freshwater, such as cloud seeding, fog harvesting, iceberg transportation to arid regions, and water recycling, they are not yet scalable enough to meet the global water demand, according to Qadir.

At present, desalination plants can produce 56 billion liters of desalinated water daily, which amounts to approximately 7 liters per person on Earth.

Out of the estimated 16,000 desalination plants worldwide, 39% are located in the Middle East, which, along with North Africa, is one of the most water-stressed regions globally.

Qadir emphasized that for many of these countries, a future without desalination would be extremely challenging. Numerous countries withdraw more water than rainfall replenishes, leading to this issue. It is worth noting that desalination only accounts for approximately 0.5% of the total water used worldwide.

However, in countries like Qatar and Bahrain, it plays a much more significant role, constituting 76% and 56% of their water supply, respectively.

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Enhanced Efficiency in Fossil Fuel-Powered Energy Systems

Desalination, although powered by fossil fuels, is becoming increasingly energy efficient. The majority of its energy comes from power plants that emit greenhouse gases.

A recent study conducted in 2021 revealed that the four desalination plants in Cyprus, the EU’s hottest and driest country, accounted for only 5% of its total electricity consumption and 2% of greenhouse gas emissions. These plants provide approximately 80% of the nation’s drinking water.

Various factors, including improved energy efficiency, contribute to the growth of the industry. Hugo Birch, the editor specializing in desalination and water reuse at Global Water Intelligence, explained that newest desalination plants now utilize reverse osmosis, a highly energy-efficient process. This switch has the potential to cut electricity costs in half.

Over the years, the energy required for reverse osmosis desalination has decreased by nearly 90% between 1970 and 2020, according to estimates. Furthermore, technological advancements are predicted to reduce the costs of desalinated water by 60% in the next two decades.

Desalination Costs Prohibitively High for Developing Nations

Desalination, the process of producing freshwater from seawater, has become more affordable in recent years, with costs decreasing to around $0.50 per cubic meter. However, this technology remains out of reach for poorer countries. According to Qadir, desalination is still primarily a business of rich countries, making it unaffordable for low-income nations.

Currently, over 90% of desalination projects are concentrated in upper-middle- and high-income countries worldwide. This is concerning, considering that poorer countries, particularly those in sub-Saharan Africa, are expected to face severe water scarcity issues by 2050.

Although there are efforts to develop smaller desalination plants powered by solar or wind energy, Qadir doubts that these solutions are effectively reaching the marginalized communities that need them the most.

Risks of Harmful Brine Pollution to Marine Ecosystems

Marine ecosystems may face potential threats from the pollution caused by toxic brine. According to Argyris Panagopoulos, a chemical engineer from the National Technical University of Athens, one of the main environmental concerns associated with desalination is the discharge of brine into the natural environment. This can lead to marine pollution, underground water pollution, and soil salinization.

The Middle East is responsible for approximately 70% of the global brine output, and their desalination plants produce a significant amount of brine compared to the desalinated water. The higher salinity of seawater, predominantly used by plants in the Middle East, contributes to this phenomenon, unlike the brackish water commonly utilized in other regions such as the US. However, measures are usually in place to prevent the dumping of brine in a concentrated area.

Fortunately, there are emerging brine treatment technologies that show promise in reducing pollution and recovering valuable materials such as minerals, salts, and metals. This could potentially help mitigate the negative impact on marine ecosystems.

Pioneering a Sustainable Path for Desalination

Although desalination has made significant strides, there remains room for improvement to guarantee a sustainable future. Panagopoulos highlights the need for better brine management and a shift towards utilizing green energy sources.

According to the chemical engineer, desalination has made progress, but there are still challenges to address before it can be deemed fully environmentally sustainable.

UN University’s Manzoor Qadir is optimistic about the role desalination will play in addressing water scarcity in the future. He emphasizes that desalination remains unaffected by climate change, making it a reliable solution regardless of weather conditions.