Kudos to John L. Daly, who has written a very interesting study of ice at the North Pole. Global Warmists are once again observing cyclical changes and declaring them "proof" of the dire effects of global warming.
Among the interesting pictures posted to this site is this one from 1987, when we were supposed to be worried about global cooling:HMS Superb, USS Billfish, and USS Sea Devil in a North Pole rendezvous in 1987
(U.S. Navy Photo)
This was not exactly a harbinger of global warming, as this picture of unbroken ice at the North Pole three years later attests:USS Hawkbill at the North Pole, Spring 1999. (US Navy Photo)
Daly explores the various factors influencing ice at the North Pole. It is accessible to laymen like me. His conclusions:
...both the extent and thickness of Arctic sea ice is certainly subject to variation. But it would be a mistake to assume that a brief period during which the Arctic is in a thinning cycle is anything more than that - a cycle. We know from past history that it has been subject to earlier retreats....
Part of the problem lay in the fact that useful data on ice extent and thickness only dates from the 1950s, yet our temperature record from Jan Mayen Island at the edge of the Arctic shows that the Arctic was warmer during the 1930s than it was during the 1990s. Unfortunately there is no comprehensive ice data from the 1930s. Instead such data begins in the late 1950s, at a time when the Arctic was entering into the grip of a known cold spell. As that cold period ended, it is hardly surprising to find thinner ice during the latter warmer period. [....]
The limits on the thickness of Arctic ice are determined by how low the air temperature can get, and on how warm and fast-moving the subsurface water is. Air temperatures measured in the Arctic region show no recent warming, thus discounting the possibility that recent thinning of ice could be caused by atmospheric warming above the ice. Rather, the thinning of ice in the 1990s is clearly associated with a warming of the sub-surface ocean, as shown by the SCICEX data, caused in whole or in part by the strong NAO [North Atlantic Oscillation -- ocean current change] increasing the flow rate of Atlantic water into the Arctic Ocean.
There is nothing in the data to suggest anything but natural cycles at work.
Hat tip: Michael Geer