Ocean water warming was believed to have initiated about 50 years ago, but is now believed to have begun over 100 years ago according to a study done by the Scripps Institution of Oceanography at UC San Diego.Īccording to a National Aeronautics and Space Administration (NASA) funded 2006 study that spanned 20 years, the combined loss of mountain glaciers and ice caps averaged 402 gigatonnes per year. There continues to be more evidence that ocean temperatures have been rising and for a longer period of time than once thought. Since there are more icebergs and they are melting faster, we can expect a bigger population of growlers and berg bits, so more danger to shipping," Wadhams explained. "The growlers and bergy bits are difficult to detect by radar and satellite, yet are still capable of damaging or sinking a ship. The smaller icebergs are known as growlers (less than 3.3 feet high by less than 16 feet long) and bergy bits (3.3 to 16 feet high by 16 to 49 feet long). Wadhams stated that warmer seas were accelerating the melting process, but at the same time are calving smaller bergs out of the larger ones. "During the past 10 years, the downhill flow rate of the Greenland glaciers has doubled in speed and is contributing to a larger number of icebergs being calved," Wadhams said.īased on a study done by the Geological Survey of Denmark and Greenland, which tracked calving of Greenland icebergs as far back as 1890, the calving rate in recent years was matched only during a period during the 1930s. Wadhams is Professor of Ocean Physics, Department of Applied Mathematics and Theoretical Physics, at the University of Cambridge, United Kingdom. Peter Wadhams, "There are more icebergs now than there were in 1912." Similarly wind and currents transport the icebergs away from the South Pole continent.Īccording to Dr. In the Southern Hemisphere, the calving occurs around Antarctica from ice shelves and glaciers. These swirls of water, combined with surface winds can transport the icebergs farther south (and east) on occasion. In the northwestern Atlantic, as the cold Labrador current interacts with the warm Gulf Stream, eddies form. From Greenland, the surviving icebergs eventually drift southward via the Labrador Current into the northwestern Atlantic Ocean. Calving occurs when pieces of the ice break off and float into the sea, or when a large iceberg breaks up into a smaller one. In the Northern Hemisphere, most of the icebergs are calved from West Greenland glaciers. The most significant problem facing shipping and detection measures has to do with the size of the icebergs. In the Northern Hemisphere, between 1 and 2 percent of all the icebergs reach southward to 48 degrees North. Interestingly, in some years there can be up to 40,000 icebergs calved. While the number of icebergs tends to vary greatly from year to year there are, on average, 15,000 icebergs born annually.
23, 2007, the MS Explorer struck submerged ice, believed to be part of an iceberg, and sank in the Southern Ocean. It is believed that the RMS Titanic struck a small- to medium-sized iceberg. Image: The greatest danger from icebergs today is from much smaller objects than portrayed here. However, despite improvements in detection methods and more accurate ship positions, as well as trending warmer seas melting the icebergs faster, ships continue to have close encounters with these frozen, floating objects.Īccording to the BBC, between 19 there have been 57 incidents with vessels involving icebergs.
Shipboard radar, satellite photos, global positioning systems (GPS) and aircraft patrols have made the North Atlantic safer now than it was during the early 1900s. One hundred years after the RMS Titanic foundered in icy waters 375 miles south of Newfoundland, the dangers of vessels striking an iceberg continue.
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