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Arctic Sea Ice: Is It Being "Transformed"?
Johannessen, O.M., Shalina, E.V. and Miles M.W.  1999.  Satellite evidence for an Arctic sea ice cover in transformation.  Science 286: 1937-1939.

What was done
Satellite passive microwave sensor data were used to derive variations in the extent of multiyear Arctic sea ice area from 1978 to 1998; while surface-based measurements were used to derive variations in area-averaged Arctic ice thickness from 1978 to 1991.

What was learned
Over the 20-year period investigated, the microwave-derived Arctic sea ice area decreased by about 14%; and from 1978 to 1991, there was a high correlation (r = 0.88) between ice thickness and ice area.

What it means
The authors state that "the balance of evidence thus indicates an ice cover in transition" and that "if this apparent transformation continues, it may lead to a markedly different ice regime in the Arctic."  Indeed, in a related News of the Week story, Kerr (1999) asks, in the very title of his commentary, "Will the Arctic Ocean lose all its ice?"

The way these several statements are structured, one gets the distinct impression that a relatively consistent and ongoing transformation (a persistent reduction of area and thickness in Arctic sea ice) is, in fact, in progress, when, according to the authors' own data, this point is highly debatable and, in our estimation, probably false.

In viewing the authors' combined temporal plot of Arctic sea ice area and thickness (their Figure 2), for example, it can readily be seen that the decline in both parameters does not occur smoothly over the whole 20-year period.  In fact, essentially all of the net drop in both parameters occurs rather abruptly over a single period of not more than three years (87/88-90/91) and possibly only one year (89/90-90/91).  Furthermore, it could be argued that from 90/91 onward, sea ice area in the Arctic may have actually increased.

We urge you to go to the authors' original Science paper and see for yourself that what we say is true.

Reviewed 1 January 2000