Deep water formation in the North Pacific and deglacial CO2 rise

Abstract

Deepwater formation in the North Atlantic and Southern Ocean is widely thought to influence deglacial CO2 rise and climate change; here we suggest that deep water formation in the North Pacific may also play an important role. We present paired radiocarbon and boron isotope data from foraminifera that suggest that, between 17.3 and 16.0 ka, deep water formation to 3600 m occurred in the North Pacific. This was likely driven by an increase in surface salinity, due to subdued atmospheric/monsoonal freshwater flux during Heinrich Stadial 1. In a series of modeling experiments we show that this stratification breakdown leads to a rapid ~30 ppm increase in atmospheric CO2, along with decreases in atmospheric δ13C and Δ14C, consistent with observations of the early deglaciation. Our work thus highlights a hitherto unrealized role for the North Pacific in contributing to deglacial CO2 rise.