New paper finds Arctic sea ice is controlled by natural cycles

A paper published today in Geophysical Research Letters finds Arctic sea ice extent is determined primarily by the natural ~60-90 year cycle of the Atlantic Multidecadal Oscillation [AMO], not greenhouse gases.

According to the authors, "Arctic sea ice is intrinsically linked to Atlantic multidecadal [natural] variability" finding a ~60-90 year cycle of "Covariability between sea ice and Atlantic multidecadal variability as represented by the Atlantic Multidecadal Oscillation (AMO) index is evident during the instrumental record."

The paper adds to many other peer-reviewed publications finding changes in Arctic sea ice are primarily related to natural variability of ocean and atmospheric oscillations, storm and wind activity, and not changes in greenhouse gases.

A Signal of Persistent Atlantic Multidecadal Variability in Arctic Sea Ice

Martin W. Miles et al

Satellite data suggest an Arctic sea ice–climate system in rapid transformation, yet its long-term natural modes of variability are poorly known. Here, we integrate and synthesize a set of multi-century historical records of Atlantic Arctic sea ice, supplemented with high-resolution paleo proxy records, each reflecting primarily winter/spring sea ice conditions. We establish a signal of pervasive and persistent multidecadal (~60–90 year) fluctuations that is most pronounced in the Greenland Sea, and weakens further away. Covariability between sea ice and Atlantic multidecadal variability as represented by the Atlantic Multidecadal Oscillation (AMO) index is evident during the instrumental record, including an abrupt change at the onset of the early 20th century warming (ETCW). Similar covariability through previous centuries is evident from comparison of the longest historical sea ice records and paleo proxy reconstructions of sea ice and the AMO. This observational evidence supports recent modelling studies that have suggested that Arctic sea ice is intrinsically linked to Atlantic multidecadal [natural] variability. This may have implications for understanding the recent negative trend in Arctic winter sea ice extent, although because the losses have been greater in summer, other processes and feedbacks are also important.