Response of atmospheric CO2 to the abrupt cooling event 8200 years ago



Atmospheric CO2 records for the centennial scale cooling event 8200 years ago (8.2 ka event) may help us understand climate-carbon cycle feedbacks under interglacial conditions, which are important for understanding future climate, but existing records do not provide enough detail. Here we present a new CO2 record from the Siple Dome ice core, Antarctica, that covers 7.4–9.0 ka with 8 to 16 year resolution. We observe a small, about 1–2 ppm, increase of atmospheric CO2 during the 8.2 ka event. The increase is not significant when compared to other centennial variations in the Holocene that are not linked to large temperature changes. Our results do not agree with leaf stomata records that suggest a CO2 decrease of up to ~25 ppm and imply that the sensitivity of atmospheric CO2 to the primarily Northern Hemisphere cooling of the 8.2 ka event was limited.