A Titanic mystery: Why were icebergs so far south?

Of all the astonishing circumstances that conspired against RMS Titanic, one belongs to the realm of nature, and it raises a question that hasn't received much attention in the last century.

Just what were icebergs doing prowling the North Atlantic at the latitude of Newport, R.I.?

Ironically, the sun may have had something to do with the answer.

Ships can encounter all sorts of hazards in that part of the Atlantic these days - and that might include icebergs - but nothing like what doomed the Titanic.

Sea-surface temperatures at the time of the sinking on that April 15 were in the upper 20s, close to the freezing level of salt water. This week they have been in the 50s, according to Oceanweather Inc.

What was different in 1912?

The disaster occurred in a period of worldwide cooling. Looking at the National Climate Data Center database dating to 1880, for 15 consecutive years before the sinking, annual global temperatures finished below long-term averages.

One intriguing theory is that the cooling got an extra kick from the 11-year sunspot cycle. NASA data show a tremendous lull in sunspots - violent solar storms that eject powerful energy into space - from late 1910 through mid-1914. Lulls have been associated with global cooling, and the activity hit rock bottom in 1913, which saw 314 days without a single sunspot.

In a paper published in 2000, British meteorologist Edward N. Lawrence opined that right before a sunspot activity reaches its lowest level, cooling reaches a peak.

Spring, as the sun gains power in the Northern Hemisphere and loosens up the ice, is an especially dangerous time for icebergs.

They are still hazards in the North Atlantic, said Alex Sosnowski, a meteorologist with Accu-Weather Inc., but those typically would be smaller ones, no higher than about 16 feet.

However, the iceberg landscape in April 1912 evidently was extreme. The Titantic ran into one as high as 200 feet. The general cooling would have bulked up the ice supply, and a warm interval off western Greenland could have caused some of that icy mass to break off. Sosnowksi thinks its possible that the icebergs got caught in an eddy and were driven southward.

The Institute for Ocean Technology, in Canada, has documented over 550 ship-iceberg collisions in the North Atlantic, dating to the mid-19th Century, but only a few have occurred at that latitude.

Rodney Viereck, a solar specialist at the government's Space Weather Prediction Center, in Colorado, believes Lawrence was on to something with the solar connection.

While no one would blame sunspots for the disaster, they may well have played a role, he said this week.

"There is significant evidence to show that the cold climate of 1912 may have been in part due to the lower level of solar energy reaching Earth relative to today," he said.

Sunspot observation has yielded some of the oldest and most-reliable data in the climate universe, said Viereck. Galileo first observed sunspots in 1612.

Precisely how subtle changes in solar energy affect Earth's climate is uncertain; the range in output is a mere 0.2 percent, according to the experts. Nor has anyone quite figured out how to separate it from other forces, such as human activity, volcanic ash, or changing ocean temperatures.

Yet solar fluctuations almost certainly have significant impacts on climate. In the heart of the Little Ice Age, none were sighted from 1661 to 1671.

While the sun may have a role in the Titanic disaster, it is certain that humans did.