In brief
With climate change exacerbating water scarcity, desalination is becoming increasingly vital for many regions, especially in the Middle East, parts of Africa, and drought-stricken areas in the U.S. The technology uses methods like reverse osmosis to convert seawater into drinkable water, but it also presents considerable environmental challenges. As the global demand for freshwater grows, so does the push for innovations to make desalination more sustainable and less harmful to marine ecosystems.
As climate change intensifies droughts, disrupts rainfall patterns, and fuels wildfires, more regions are turning to the sea for drinking water.
Desalination, which is the process of removing salt from seawater, offers a way to produce freshwater in regions that lack sufficient rain, rivers, or groundwater to meet demand. Today, it supplies water to hundreds of millions of people worldwide, from the Middle East to the U.S., and its use is growing as water scarcity deepens.
Here’s what you need to know.
How it works
Most modern desalination plants rely on a process known as reverse osmosis. Seawater is forced at high pressure through a semi-permeable membrane that allows water molecules to pass through while blocking most salts and other impurities. After treating, the freshwater meets drinking water standards.
An alternative method, thermal desalination, involves heating seawater until it evaporates and condensing the vapor back into liquid, leaving the salt behind.
Countries like Kuwait and Oman derive more than 85% of their drinking water from these processes as of a 2022 report. The global operation count of desalination plants has now surpassed 20,000 and is expanding rapidly at an annual rate of about 7% since 2010, as reported by the International Desalination and Reuse Association.
Environmental and Economic Trade-offs
While desalination plays a critical role in addressing freshwater shortages, it comes with significant trade-offs. The process is energy-intensive, contributing an estimated 500 to 850 million tons of carbon emissions annually, nearly equivalent to the global aviation industry's emissions. Furthermore, concentrated brine, a byproduct of desalination, can disrupt coastal ecosystems.
Efforts to mitigate these impacts are underway, including utilizing renewable energy sources and advancing membrane technology to enhance efficiency. As the demand for freshwater continues to rise, experts advocate prioritizing water reuse and conservation as alternatives to desalination.
Ultimately, as nations grapple with climate-related water shortages, desalination stands at a crossroads of necessity and sustainability.
