Timothy Birdnow



North America has cooled since 1998, and this wipes out a nominal warming, leading to no warming since 1982, according to a new study.

From No Tricks Zone:

The Key Role of Atlantic Multidecadal Oscillation
in Minimum Temperature Over North America
During Global Warming Slowdown

"Daily Minimum temperature (Tmin) is an important variable in both global and regional climate changes, and its variability can greatly affect the ecological system. In the early 21st century, warming slowdown is seen over the North Hemisphere and North America is one of the major cooling centers.”

"In this study, we found that Tmin experienced an obvious decline in North America during warming slowdown period. Such Tmin decline is closely related to the Atlantic Multidecadal Oscillation (AMO), the correlation between the decadal components of Tmin and AMO reached 0.71 during 1950-2014.”

"According to composite analysis, the AMO on the positive (negative) phase takes two low-pressure (high-pressure) systems in the northeastern Pacific and the North Atlantic at night, accompanied by cyclonic (anticyclonic) circulations and warm (cold) advection in North America. Therefore, the analyses conclude that the Tmin decline during warming slowdown period is a result of the synchronous decrease of the AMO. The results emphasize the key role of AMO on the decadal variation of Tmin in North America.”

Image Source: Gan et al., 2019

Another new paper renews the global warming "hiatus” debate and documents a 21st century cooling trend in northern China that also effectively snuffs out the previous decades of warming for the region.

Posted by: Timothy Birdnow at 08:31 AM | Comments (7) | Add Comment
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