Climatic changes threaten to change the ocean currents that moderate the temperatures in the northern part of the planet. The result of global warming could actually be an ice age. The expected damage: hundreds of billions of dollars
Margaret Monroe
Photo: AP - A ship makes its way through the frozen Baltic Sea on its way to Sweden. The sea crossings may be blocked
Drastic changes in the North Atlantic Ocean could disprove the conventional wisdom, according to which the Earth will gradually warm up due to the gases of the greenhouse effect in the atmosphere. Global warming will usher in an ice age that could last for centuries.
"Last year we saw ominous signs," says Dr. Robert Gagosian, president and director of the Woods Hole Oceanographic Institution in Massachusetts. "Earth's climate may 'change gears' and jump very quickly, rather than gradually, to a completely different course of action than we expected."
Gagosian bases his words on accumulating evidence, according to which climatic changes threaten the ocean current that moderates temperatures in the northern part of the planet. Without this current, London - located at almost the same latitude as Edmonton in Canada - would suffer from much longer and colder winters. Without this current, the potatoes growing on Prince Edward Island in Canada would become a thing of the past.
There is no novelty in talk of climate change that could trigger the sudden onset of an ice age. Gagosian believes that the danger is tangible and warns that these changes may occur in our lifetime. Once the cooling begins, he says, it could develop rapidly, and within a decade temperatures will drop several degrees Celsius in large parts of the United States, Canada and Europe. Rivers, harbors and sea lanes will freeze much sooner than they do now, and the effects on transport, agriculture and fishing will be devastating. "In short, the world and the world economy will change drastically," he added.
His controversial predictions are based on data collected in the North Atlantic Ocean. Igor Yeshayav, from the Bedford Institute of Oceanography in Nova Scotia, and his colleagues in Great Britain, the United States and Germany, discovered that the body of water in the Labrador Sea has undergone a radical change in the last 40 years. Information collected in the Labrador Sea and in the areas between Greenland, Iceland and Europe - shows that the North Atlantic Ocean has become less salty, especially in the last decade.
Scientists do not know for sure what the source of the fresh water is. They suspect that a large part of them came from the polar region, where the ice is melting at an alarming rate. Gagosian and his colleagues say the influx of fresh water could block the "great ocean conductor," the main system that conducts heat in the ocean and drives the Gulf Stream, which carries heat from the tropics to the north.
When the Gulf Stream reaches Labrador and Greenland, its waters cool, sink into the ocean and create a void that pulls more warm tropical water northward. Fresh water is lighter and less likely to sink. Scientists fear that fresher water flowing into the North Atlantic could slow the Gulf Stream, push it south, and worse: shut down the conduit system entirely. Already, the water in the Greenland Sea is sinking at a rate 20% slower than it was in the XNUMXs. This reduced salinity is "the largest and most dramatic change in ocean properties ever measured in the ocean," Gagosian said. He added that it is not known at what rate the oceanic conductor will be stopped. "This is not a switch that dims lighting, but a switch that turns it off. It will probably go from activation to paralysis."
Not everyone is sure that the conductor is in danger. Eddie Carmack, an oceanographer at the Institute of Ocean Sciences in Sydney, is not convinced that the softening of water in the North Atlantic will lead to sudden climate change. "However, what is at stake is so important that the possibility cannot be ruled out," he said.
Allin Clark, who heads the Canadian team examining the conditions in the Labrador Sea, defined the evidence of the fresh water in the North Atlantic Ocean as "shocking".
Changes in ocean temperatures have previously been associated with ice ages. About 12,800 years ago, the water temperature in the North Atlantic dropped dramatically. According to Gagosian, it then took only about ten years to move into an ice age that lasted approximately 1,300 years. "The last time the movement of currents in the North Atlantic Ocean stopped was, according to information, 500 years ago. It imitates northern settlements and vineyards that thrived in Greenland." A report recently published by the American National Academy of Sciences notes that climate changes occurred in the past "with incredible speed." The cost of damages from such a change nowadays could be, according to the authors of the report, 250-100 billion dollars.
"The climate system can go from one climate state to another within decades," Clark said. "If such a change does occur, we have no idea how we will try to stop the system or reverse the trend."
