A STRIKING shift in the deep water currents of the Mediterranean is the first hard evidence that climate change might cause stable ocean currents, such as the Gulf Stream, to "flip" into a new and potentially dangerous state. Climate modellers have predicted such flips, but the discovery by German scientists provides the first hint of such a change.
Wolfgang Roether of the University of Bremen and colleagues cruised the eastern Mediterranean aboard the German research ship Meteor last winter. They discovered an inversion in the temperature and salinity gradient of the deepest water, with the temperature increasing with depth rather than cooling.
"Normally, the temperature falls from 13.5 °C to 13.3 °C between 1200 metres and the bottom - around 3000 metres," says Roether. "Now it goes from 13.5 °C to around 13.8 °C." At the same time the salinity at the bottom has increased by 0.02 per cent. This ...
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