Background
Climate alarmists vociferously contend that global warming causes weather to become more variable, leading to greater extremes of precipitation and, consequently, enhanced severity of droughts and floods. The paper reviewed here contributes to the examination of this claim as it pertains to central Asia.

What was done
In the words of the authors, "absolutely dated tree-ring-width chronologies from five sampling sites in west-central Mongolia were used in precipitation models and an individual model was made using the longest of the five tree-ring records (1340-2002)." This work also led to a reconstruction of streamflow that extends from 1637 to 1997.

What was learned
Davi et al. discovered there was "much wider variation in the long-term tree-ring record than in the limited record of measured precipitation," which for the region they studied covered the period from 1937 to 2003. In addition, they report that the streamflow history they created indicates that "the wettest 5-year period was 1764-68 and the driest period was 1854-58," while "the most extended wet period [was] 1794-1802 and ... extended dry period [was] 1778-83."

What it means
For this important part of Mongolia, which the researchers say "is representative of the central Asian region," there is no support to be found for the climate-alarmist contention that the "unprecedented warming" of the 20th century has led to increased variability in precipitation and streamflow. In fact, any tendencies that may be present in the data suggest just the opposite.