Desalination grows as water scarcity deepens.

Desalination is being used more widely as drought and changing rainfall reduce freshwater supplies; the article reports more than 20,000 plants worldwide and industry growth of about 7% annually.

Desalination is being used more widely as droughts and shifting rainfall make freshwater scarce. The process removes salt from seawater to produce drinking water, and most modern plants rely on membrane-based methods such as reverse osmosis. Desalination already supplies water to hundreds of millions of people and the industry has expanded in many regions, including parts of the Middle East, Australia, Africa and the U.S. Discussion of the technology now centers on its energy use and effects on marine ecosystems. Key points: - Reverse osmosis is the dominant method, using membranes to separate freshwater from seawater. - The article reports more than 20,000 desalination plants worldwide and industry growth of about 7% annually since 2010. - Desalination is energy intensive and is reported to produce roughly 500–850 million tons of carbon emissions annually; it also generates concentrated brine that is typically discharged into the ocean. - Reported responses include powering plants with renewable energy, developing more efficient membranes, experimenting with deep-sea approaches, and prioritizing wastewater recycling and conservation as lower-energy alternatives. Summary: Desalination is expanding as a source of drinking water while raising concerns about energy use and marine impacts. Industry and researchers are testing lower-carbon power and efficiency measures, and experts highlight wastewater recycling and conservation as important parts of the broader response. How broadly desalination will be deployed relative to other water strategies remains undetermined at this time.