Reference
Linderholm, H.W. and Chen, D. 2005. Central Scandinavian winter precipitation variability during the past five centuries reconstructed from Pinus sylvestris tree rings. Boreas 34: 44-52.
What was done
A 500-year winter (September-April) precipitation chronology was derived from tree-ring data obtained within the Northern Boreal zone in west-central Scandinavia in an effort to better understand historic precipitation variability in this region.
What was learned
The reconstructed chronology showed considerable variability in winter precipitation over the length of the record, with the exception of a fairly stable period of above-average precipitation between 1730 and 1790 AD. Additionally, above average winter precipitation was found to have occurred in 1520-1561, 1626-1647, 1670-1695, 1732-1851, 1872-1892 and 1959 to the present, with the highest values reported in the early to mid-1500s. Below average winter precipitation was observed during 1504-1520, 1562-1625, 1648-1669, 1696-1731, 1852-1871, and 1893-1958, with the lowest values occurring at the beginning of the record and the beginning of the 17th century.
What it means
Because non-CO2-forceced wetter and drier conditions than those of the present have occurred in this region in the past, such conditions can be expected to naturally recur in the future. Yet just as soon as the precipitation balance begins to tip towards one extreme or the other, you can count on there being a number of climate alarmists who will be all too eager to attribute the change to the ongoing rise in the air's CO2 content, even when such attribution is clearly unwarranted.