Science
DOI:
The regional climates of the North Pacific and North Atlantic fluttered between synchrony and asynchrony during the last deglaciation, with correspondingly more and less intense effects on the rest of the world, researchers have found. The climate system can be highly nonlinear, meaning that small changes in one part can lead to much larger changes elsewhere. This type of behavior is especially evident during transitions from glacial to interglacial conditions, when climate is affected by a wide variety of time-varying influences and is relatively unstable. Praetorius and Mix present a record of North Pacific climate over the past 18,000 years. When the climates of the more local high-latitude Pacific and Atlantic sectors varied in parallel, large, abrupt climate fluctuations occurred on a more global scale.
Some proposed mechanisms for transmission of major climate change events between the North Pacific and North Atlantic predict opposing patterns of variations; others suggest synchronization. Resolving this conflict has implications for regulation of poleward heat transport and global climate change. New multidecadal-resolution foraminiferal oxygen isotope records from the Gulf of Alaska (GOA) reveal sudden shifts between intervals of synchroneity and asynchroneity with the North Greenland Ice Core Project (NGRIP) δ18O record over the past 18,000 years. Synchronization of these regions occurred 15,500 to 11,000 years ago, just prior to and throughout the most abrupt climate transitions of the last 20,000 years, suggesting that dynamic coupling of North Pacific and North Atlantic climates may lead to critical transitions in Earth’s climate system.