What was done
The authors studied spatial and temporal patterns of land degradation in northeastern Iceland over the past 7500 years based on data obtained from excavations of 67 soil profiles, comparing their results with climatic variations known to have occurred over the same period.

What was learned
The authors report that "the [periodic] deterioration in vegetation and soil cover noted [in their study] coincides with the recorded [periodic] deterioration in climate."  In fact, during every major cold period of their entire record, land degradation is classified as "severe."  During every major warm period, on the other hand, this condition is reversed, and soils are built up again, as vegetation cover also expands.

What it means
In the words of the authors, "the implication is that climate has a significant role in altering land cover per se and may trigger land degradation without the additional influence of men."  They conclude that "grazing can be seen as a contributing factor, [but] not as the major triggering factor as is commonly believed."  Hence, they reiterate that "in Iceland severe land degradation could commence without anthropogenic influence - simply as a result of the cold periods."