Climate Change Alters Salt Levels in Atlantic Ocean, to Europe’s Dismay

The Atlantic Ocean seems so vast that it’s almost impossible to imagine fundamentally altering it — and yet, its salt levels have changed so drastically over the last 40 years because of global warming that the whole flow of ocean water is being disrupted, according to a study published today in the journal Nature. As the planet warms, more ocean water evaporates than normal, causing the concentration of salt to increase in certain areas — and, because the overall salinity of the ocean must remain the same, to decrease in others. Because salty water is heavier than fresh water, these changes alter the way ocean water flows around the planet. In a kind of vicious climate-change circle, that alteration will have its own dramatic effects on the global climate, changing and redirecting such basic forces as the Gulf Stream, which keeps places like England and Ireland relatively warm and inhabitable, even though they share the same latitude as the far colder southern Alaska. If ocean salinity continues to change, the Nature study found, Northern Europe could become as much as 10 to 20 degrees cooler than it is today.