Ice core records of atmospheric CO₂ provide valuable insights into global carbon cycle dynamics. This study presents high-resolution CO₂ and CH₄ measurements from the Skytrain ice core (1450-1700 CE), suggesting a gradual CO₂ decrease (0.5 ppm per decade) from 1516 to 1670 CE, implying a land carbon sink of 2.6 PgC per decade. This finding supports models of land-use reorganization in the Americas post-New World-Old World contact, contradicting the rapid CO₂ decrease at 1610 CE observed in the Law Dome record, which is potentially an artifact.

Amy C. F. King, Thomas K. Bauska, Edward J. Brook, Mike Kalk, Christoph Nehrbass-Ahles, Eric W. Wolff, Ivo Strawson, Rachael H. Rhodes, Matthew B. Osman