New Research Finds Human Impact is Leading to Higher Salinity Levels in Freshwater Resources

December 14, 2018

SEASIDE, Ca., December 14, 2018 – A study conducted by California State University, Monterey Bay (CSUMB) School of Natural Sciences assistant professor John Olson has found that the combined effects of land use and climate change are resulting in increased salinity levels in rivers and streams, further highlighting an emerging threat to freshwater resources, biodiversity and ecosystem functions across the United States.

CSUMB School of Natural Sciences assistant professor John Olson.

CSUMB School of Natural Sciences assistant professor John Olson.

Increase in human land use such as agricultural, industrial and urban development are primary contributing factors to increasing salt levels, with climate change accounting for 12 percent of the increase.

Olson estimated that at least one third of U.S. streams and rivers have gotten saltier over the last 100 years and predicted that salinization levels may rise by 50 percent in half of U.S. streams by the year 2100. While increased salinity levels pose a problem for drinking water, they may also double the amount of streams that are too salty for irrigation from 3 to 6 percent, compounding losses of water resource availability caused by increasing droughts and other climate change effects.

Most of these losses of irrigation water will occur in areas like the Great Plains and Southwest where water is already scarce, but modest increases in salinity that will impact freshwater ecosystems will be widespread.”
— CSUMB School of Natural Sciences assistant professor, John Olson.

The effects of increased salinity levels are not limited to salt’s effects on humans. The research also predicts that increased salinity levels will stress biota within the ecosystem resulting in losses of an additional 42 percent of the habitat by 2100.

Salinity of freshwater is not something we think about a lot, but without careful management we risk making water too salty, both for us and for the plants and animals that live in freshwater.”

The research study, Predicting combined effects of land use and climate change on river and stream salinitywas first published in the journal Philosophical Transactions B, on December 4, 2018 and later featured in the Scientific American.