2005: Global Warming Makes Atlantic Ocean Less Salty

Since the late 1960s, much of the North Atlantic Ocean has become less salty, in part due to increases in fresh water runoff induced by global warming, scientists say.  Now for the first time researchers have quantified this fresh water influx, allowing them to predict the long-term effects on a “conveyor belt” of ocean currents.

Climate changes in the Northern Hemisphere have melted glaciers and brought more rain, dumping more fresh water into the oceans, according to the analysis.

One of the expected high-profile consequences is a rising sea that will swamp coastal communities.
http://www.livescience.com/environment/050629_fresh_water.html

2007: Global Warming Makes Atlantic Ocean More Salty

The surface waters of the North Atlantic are getting saltier, suggests a new study of records spanning over 50 years. And this might actually be good news for the effects of climate change on global ocean currents in the short-term, say the study’s researchers.

This is because saltier waters in the upper levels of the North Atlantic ocean may mean that the global ocean conveyor belt – the vital piece of planetary plumbing which some scientists fear may slow down because of global warming – will remain stable.

The global ocean conveyor belt is the crucial circulation of ocean waters around the Earth. It helps drive the Gulf Stream and keeps Europe warm. The density of waters which drives the flow of ocean currents is dependent on temperature and salinity, so any change in saltiness may have an impact.

Tim Boyer of the US National Oceanographic Data Center and colleagues compiled salinity data gathered by fisheries, navy and research ships travelling across the North Atlantic between 1955 and 2006. They found that during this time, the layer of water that makes up the top 400 metres has gradually become saltier.

The seawater is probably becoming saltier due to global warming, Boyer says. “We know that upper ocean is warming in the North Atlantic, so it stands to reason that there should be more evaporation, making waters more salty,” he says.
http://environment.newscientist.com/article.ns?id=dn12528&feedId=online-news_rss20