Central Pacific El Nino and decadal climate change in the North Pacific Ocean

Decadal fluctuations of the ocean and atmosphere over the North Pacific Ocean significantly affect the weather and climate of North America and Eurasia. They also cause transitions between different states of marine ecosystems across the Pacific Ocean(1-3). An important fraction of North Pacific low-frequency variability is linked to the North Pacific Gyre Oscillation(4), a climate pattern associated with decadal fluctuations of the ocean circulation. Decadal variations in the North Pacific Gyre Oscillation are characterized by a pattern of sea surface temperature anomalies that resemble the central Pacific El Nino, a dominant mode of interannual variability with far-reaching effects on global climate patterns(5-7). Here we use an ensemble of simulations with a coupled ocean-atmosphere model to show that the sea surface temperature anomalies associated with central Pacific El Nino force changes in the extra-tropical atmospheric circulation. These changes in turn drive the decadal fluctuations of the North Pacific Gyre Oscillation. Given that central Pacific El Nino events could become more frequent with increasing levels of greenhouse gases in the atmosphere(8), we infer that the North Pacific Gyre Oscillation may play an increasingly important role in shaping Pacific climate and marine ecosystems in the twenty-first century.