Icebergs Nineteenth Century

Icebergs

Iceberg Occurrences from the book "White Wings" by Henry Brett, fifty years of sail in the New Zealand trade, 1850 to 1900.
Also reference from "The Log of the Cutty Sark" by Basil Lubbock.

"White Wings" a book of 365 pages, consists of accounts of sailing ship voyages to NZ collected by Henry Brett from his many years as a shipping reporter in Auckland last century. Mr. Brett, like any good reporter aimed to be the first person to board a ship on arrival to get first hand news from "home".

Mr. Brett took a keen interest in events on the voyage and obviously had great empathy with the era of sail.

A quick look through the book reveals some references to icebergs sighted on passage. The extreme danger that icebergs presented to shipping was obviously well known by all.

In the 1990's and currently there are common news accounts of ice shelves breaking up, or large icebergs being sighted by satellite, the implication is often made that this somehow reflects "greenhouse - global warming" induced climate change.

Five interesting references to marine ice from "White Wings" follows which all seem further north than one might expect these days. In case 3 the 'berg 40 to 50 miles long shows that these large icebergs are nothing new, as current media articles try to suggest.

[1] On January 2, 1868 the 1326 ton clipper "Mermaid" arrived in Lyttelton after an 89 day passage from GB and it was reported that, " When in the vicinity of Cape Leeuwin, Captain Rose and his officers had an anxious time avoiding 30 huge icebergs." Are icebergs seen off Albany or Margaret River ever these days ?

[2] In February 1877, the "City of Auckland" was 1200 miles WNW of Cape Horn and ran into a patch of icebergs with fog which kept them all busy for an afternoon. How common would this be these days in summer ?

[3] In 1893 (after arriving in Nelson in September 92), the iron sailing ship "Margaret Galbraith" was homeward bound around Cape Horn. Mr. N.H. Burgess the 2nd Officer reported that from three days north of the Falklands to about one weeks sailing north of the Falklands they were "among the ice," which culminated with a days sailing past a single giant berg "40 to 50 miles long," The account suggest the ship may have been only making 3 to 5 knots around this time, certainly at night one would expect them to throttle back. They had a close call on first encountering the ice north of the Falklands.
It may be partly by chance that the length of this iceberg was reported because the sailing people seemed more impressed by the height of ice encountered than the extent of any particular piece. The 40 to 50 mile long berg mentioned above was reported as being 1000 ft asl at the NE end.

[4] The same "Margaret Galbraith" on a 123 day passage to Napier arriving 15, January 1895, was surrounded by ice for six days in the vicinity of 44 S Latitude and 25 E Longtitude.

[5] The 1000 ton plus iron sailing ship "Himalaya", on a 109 day voyage from Liverpool to Wellington, departed 9, November 1894 and arrived 25, February, 1895. The captain reported seeing several icebergs off the Cape (of Good Hope) and then, ".. that from the Cape to the Crozets was a most trying time as icebergs were in sight for a distance of two thousand miles."

Another reference to icebergs further north than "normal" is found in Basil Lubbock's book, The Log of the "Cutty Sark".
Starting on page 282 after recounting episodes on a voyage around Cape Horn in February when Cutty Sark encountered a large ice field (including icebergs ~20 miles long) starting north of the Falkland Islands at 50 degrees north.
Lubbock says; "This ice was encountered by every ship bound round the Horn in 1892 and 1893, and extended from 44 degrees to 55 degrees South and from 25 degrees to 52 degrees West. Evidently a huge continent of Antarctic ice had broken adrift during the summer weather, and was in the grip of the current slowly working north."
This summary by Basil Lubbock corroborates the statements in [3] above from the crew of the "Margaret Galbraith".
Clearly if ice occurred today as described here there would be major media and "greenhouse industry" articles linking this to greenhouse warming.

Comments: Clearly we can not blame greenhouse induced global warming in the late 1800's for these icebergs. However it must be understood that earths temperature has been rebounding from the chill of the Little Ice Age and still is. The Little Ice Age occurred a few hundred years ago and was manfested by events such as ice skating on the River Thames, the Baltic Sea was known to freeze over etc. Of course a few hundred years earlier citizens enjoyed the Medieval Optimum when there were farming settlements on Greenland. To get back to the 1800's, it is possible that icebergs were more frequent and further north than they are now in the Southern Hemisphere as the Little Ice Age ice shelves reduced around Antarctic. There are many Australian temperature records that show the 1890's was a warm period (comparable with now) and it was the time of Australia's greatest drought. More about this later.

Length of Day Data: Two items from different sources have come to hand that add to the above observations of sea ice.
[1] The following "Length of Day" LOD, data was sent by Gary Sharp and James Goodridge and shows clearly that the unusual northerly extent of icebergs recorded by late 19C sea Captains in "White Wings", corresponds with a period of rapidly increasing LOD. This, as Bob Foster explains below, could relate to the preservation of the globes angular momentum as ice mass at high lattitudes is transferred to water mass at the equator.

[2] The following extract from Bob Foster's June, 2000 paper explains the mechanism which could relate the iceberg fleets in the late 19C with LOD changes. To access this paper and a later one, go to Guests page.
Extract from page 9 of paper by Bob Foster.

CLIMATE-CHANGE SCIENCE AND THE KYOTO PROTOCOL

Robert J. Foster,
Consultant, Melbourne Australia

Start page 9;
The basinal geometry of the southern waters is relatively simple, and there is a stability in southern climate which the north does not enjoy. Climate is unstable in the northern North Atlantic Basin mega-region because either the northerly flow of warm water penetrates between Scotland and Iceland, or it doesn’t - with a large and abrupt impact on climate.

The key to explaining abrupt climate changes in the Northern Hemisphere is provided in a series of papers by Mörner from 1984, culminating in 1996. When ice at high latitudes surges into the sea, whether just extending its adjacent ice-shelf, or moving off as icebergs, it raises sea level around the world.

Continental ice launched at high latitudes becomes water in equatorial seas, and the Globe’s radius of gyration increases as a result.

Angular momentum must be preserved; hence the Globe slows down, and length-of-day increases. But the oceans are not glued to the earth’s crust, and the linear momentum of the great ocean flows must also be preserved. The flow most vulnerable to even minor adjustments in trajectory relative to its basinal boundaries, for reasons of geometry, is that which carries tropical heat via the Atlantic into the Arctic.

The Little Ice Age is a time - the latest of many - of reduced flow of Atlantic water into the Arctic. In this instance, surging of continental ice from Greenland appears to have been the cause of the inertial effects whose outcome was a diversion of warm northerly flow away from the Scotland-Iceland gap. Especially cold intervals within the Little Ice Age correlate well with known periods of reduced solar insolation - particularly the Maunder minimum of sunspot activity of AD 1645-1715.

Rebound from the Little Ice Age since the mid 19th Century appears to have two causes. The most fundamental is the rejuvenation of the flow of warm water into the Nordic Seas and Arctic Ocean. The other, probably lesser though still important, cause is the increase in solar warmth since the 18th Century.

One last point is worth making. Whether the ice enters the sea from Greenland or Antarctica should make no difference. The inertial impact will be manifest as climate change in the northern North Atlantic Basin. The current surging of ice streams in both West Antarctica and Greenland needs to be watched - in relation to their potential impact on northern climate.

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