Abrupt Climate Change
New Study Reports Large-scale Salinity Changes in
the Oceans
(Enlarged figure)
Tropical Atlantic surface waters have become
saltier...
Tropical and subtropical Atlantic waters have become dramatically
saltier over the past 40 years, especially in the past decade,
scientists reported today in Nature. Global warming may be intensifying
evaporation, adding more fresh water vapor to the atmosphere and leaving
tropical oceans relatively saltier. The evidence suggests that recent
climate changes may be accelerating the fundamental planetary system
that transports and cycles fresh water around the globe, which could
trigger or amplify other significant climate changes.
...while North Atlantic deep water have become fresher. Over the
same 40-year period, deep waters have become less salty in critical
North Atlantic locations, where salty, dense waters sink to drive the
global ocean circulation system called the Ocean Conveyor. If the North
Atlantic becomes too fresh, its waters could stop sinking, and the
Conveyor could slow down, causing widespread climate disruptions. This
freshening trend has accelerated in the past decade, and a mass of
fresher deep water is spreading southward.
Data from Ruth Curry. Illustration İRuth Curry and Jack Cook, Woods
Hole Oceanographic Institution.