![]() In this study we use an ocean model simulation of the last 20 kyr to better understand how different age tracers, such as radiocarbon, are influenced by changes in the Pacific Ocean circulation over this period. To determine these changes, scientists often use a combination of models and data from ocean sediments and ice cores (referred to as proxy records). This transition resulted in major changes in global temperature, sea level, and ocean circulation. Key Pointsĭuring the last 20 thousand years (kyr) Earth's climate changed dramatically, transitioning from a cold climate in which ice sheets covered much of the Northern Hemisphere, to the warmer climate we experience today. As the deglaciation proceeds, circulation change controls progressively more of the Δ 14C age, accounting for more than 75% of it across the deep Pacific from 15 to 8 ka BP. A multi-millennial weakening of the overturning circulation from 20 to 15 ka BP leads to increases in deep Pacific Δ 14C ages, but from 20 to 18 ka BP, nearly half (40%–60%) of this aging is controlled by changing surface reservoir age, corroborating previous studies showing that Δ 14C is not solely a circulation age tracer. ![]() Throughout the deglaciation, the Pacific Ocean circulation in C-iTRACE responds strongly to glacial meltwater forcing, leading to large changes in deep Pacific Δ 14C age. Here we use the C-iTRACE simulation, a transient ocean-only, isotope-enabled version of the Community Earth System Model, to better understand deglacial deep Pacific radiocarbon evolution in the context of circulation and reservoir age changes. Although proxy records have significantly improved our understanding of climate during this period, questions remain regarding the connection between ocean circulation evolution and resulting geotracer distributions, including those of deep waters in the Pacific. ![]() During the last deglaciation Earth’s climate experienced strong and abrupt variations, resulting in major changes in global temperature, sea level, and ocean circulation. ![]()
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