Global Warming

Increasing Arctic freshwater is driven by climate change

New, first-of-its-kind research from CU Boulder shows that climate change is driving increasing amounts of freshwater in the Arctic Ocean. Within the next few decades, this will lead to increased freshwater moving into the North Atlantic Ocean, which could disrupt ocean currents and affect temperatures in northern Europe.

Since the 1990s, the Arctic Ocean has seen a 10% increase in its freshwater. That’s 2,400 cubic miles (10,000 cubic kilometers), the same amount it would take to cover the entire U.S. with 3 feet of water.

The salinity in the ocean isn’t the same everywhere, and the Arctic Ocean’s surface waters are already some of the freshest in the world due to large amounts of river runoff.

This freshwater is what makes sea ice possible: it keeps cold water at the surface, instead of allowing this denser liquid to sink below less dense, warm water. In this way, the Arctic Ocean is much different than other oceans. But as more freshwater exits the Arctic, this same stabilizing mechanism could disrupt the ocean currents in the North Atlantic that moderate winter temperatures in Europe.

Such disruptions have happened before, during the “great salinity anomalies” of the 1970s and 80s. But these were temporary events. If too much cold freshwater from the Arctic continuously flows into the North Atlantic, the ocean turnover could be disrupted more permanently.

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