What was done
The authors used "a ringwidth chronology developed from living, historical and subfossil bur oak (Quercus macrocarpa (Michx.)) in the Red River basin to reconstruct annual precipitation in southern Manitoba since A.D. 1409."

What was learned
In the words of the authors, "prior to the 20th century, southern Manitoba's climate was more extreme and variable, with prolonged intervals that were wetter and drier than any time following permanent Euro-Canadian settlement."  Indeed, they say that "climatic case studies in regional drought and flood planning based exclusively on experience during the 20th century may dramatically underestimate true worst-case scenarios."  They also note that "multidecadal fluctuations in regional hydroclimate have been remarkably coherent across the northeastern Great Plains during the last 600 yr," and that "individual dry years in the Red River basin were usually associated with larger scale drought across much of the North American interior."

What it means
Once again, it is easy to see that climate alarmists who tell us global-warming scare stories have got things just backwards.  They claim that both floods and droughts become more prolonged and severe when the climate warms, as it did during the 20th century when the earth recovered from the global chill of the lengthy Little Ice Age.  But the world of nature - the real world - tells us a very different story, as the data from this study clearly demonstrate.  Floods and droughts - in this case, over a large portion of the North American Great Plains (see Floods and Droughts in our Subject Index for other cases) - typically become less prolonged and severe when it warms.