Saltier North Atlantic Should Give Currents A Boost

New Scientist ^ | 8-23-2007 | Catherine Brahic

[blam]

Saltier North Atlantic should give currents a boost

13:12 23 August 2007
NewScientist.com news service
Catherine Brahic

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.

Polar 'pulse'

The global ocean conveyor belt is in part driven by salty and relatively dense subpolar waters sinking and flowing south to the equator.

So when a huge "pulse" of less dense freshwater was found to have been dumped into the sub-polar waters of the North Atlantic

[blam]

Posted on 12-1-2005.

Scientists Say Slower Atlantic Currents Could Mean a Colder Europe

[taxesareforever]

Global warming scientists covering up their butts.

[saganite]

More proof that scientists don’t have a firm grasp on global weather. Just last year they were saying that global warming was going to shut down the Atlantic conveyor. Now they say global warming might have a salutory effect on it.

[Man50D]

Is that Al Gore I see on the bottom?

[SampleMan]

Does anyone remember the POS television special about 10-15 years ago that seriously stated that the conveyor would stop completely by 2010 or so if global warming weren’t immediately stopped?

If anyone remembers, I need the name.

[neverdem]

Thanks for the ping and link.

[Libertarianize the GOP]

This can’t be correct; the sea level is rising, more freshwater is entering the oceans from all the melting glaciers and according the the global warming theory the oceans become less salty. Global Warming theory is unquestionable therefore this data must be wrong.

[ZGuy]

I guess they can have their cake and eat it too:

Global Warming Makes Sea Less Salty

[SunkenCiv]

We don't know much about the Atlantic Ocean currents
by Chris Lee
August 16, 2007

We reported on the first results from a long-term study two years ago. This study used a string of buoys running along a constant meridian to send back a continuous stream of depth-dependent flow rates. The results didn't look good -- the initial findings indicated a 30 percent slow down over 12 years. As noted by the researchers at the time, the data was noisy and that the slow down they measured could all be part of the current's internal variability.

This warning was borne out by follow up results that used new data from the buoy line and combined it with pre-existing data from other sources to get a picture of how the current... err... ebbed and flowed. Their conclusion was that all the data taken thus far fits within the bounds of natural variation.

Nevertheless, the data set is still quite sparse but the buoys are still out there. Now, in a paper to be published in Science, the researchers have analyzed the 2004-2005 data set to estimate how long it will take to obtain enough data to be sure that the internal variability of the ocean current is properly bracketed. Their answer? Ten years.

Climate change is 100 per cent natural 100 per cent of the time.