|Title:||A new high-precision record of δ13C of CO2 during the last millennium from the WAIS Divide Ice Core|
|Author:||Bauska, T.K., Brook, E.J., Mix, A.C. and Ahn, J.|
|Periodical:||EGU General Assembly 2012, held 22-27 April, 2012 in Vienna, Austria., p.599|
High-resolution ice core records from Antarctica reveal multi-decadal scale variability in atmospheric CO2 during the Late Pre-industrial Holocene. The mechanisms behind these variations remain elusive, but are important in constraining natural carbon-climate feedbacks. Additionally, recent data suggesting a Pre-industrial anthropogenic influence on atmospheric CO2 (Nevle, 2011) conflict with results of coupled climate-carbon models (Pongratz, 2011). The stable isotopic composition of carbon dioxide (δ13C of CO2) offers a tool to determine the nature and strength of carbon dioxide sources to the atmosphere.
A new high-precision (<0.02 per mil), high-resolution (~30 year sample spacing) record of δ13C of CO2 from 1000-1870 C.E. reveals previously unobserved variability in the δ13C of CO2 during periods of rapid changes in CO2. A rapid 0.1 per mil 13C depletion coincides with a 3 ppm increase in CO2 around 1500 AD, and is followed by a trend towards enriched values during a 6-7 ppm decrease in CO2 from ~1575-1650 . Modeling of the carbon cycle will help to deconvolve the source history of atmospheric CO2.