GENEVA — Scientists have found evidence of a "drastic" shift since the 1970s in north Atlantic Ocean currents that usually influence weather in the northern hemisphere, Swiss researchers said on Tuesday.
The team of biochemists and oceanographers from Switzerland, Canada and the United States detected changes in deep sea Atlantic corals that indicated the declining influence of the cold northern Labrador Current.
They said in the US National Academy of Science journal PNAS that the change "since the early 1970s is largely unique in the context of the last approximately 1,800 years," and raised the prospect of a direct link with global warming.
The Labrador Current interacts with the warmer Gulfstream from the south.
They in turn have a complex interaction with a climate pattern, the North Atlantic Oscillation, which has a dominant impact on weather in Europe and North America.
Scientists have pointed to a disruption or shifts in the oscillation as an explanation for moist or harsh winters in Europe, or severe summer droughts such as in Russia, in recent years.