Climate evolution across the Mid-Brunhes Transition

• Published in: Climate of the Past
• Main Authors: Barth, Aaron M., Clark, Peter U., Bill, Nicholas S., He, Feng, Pisias, Nicklas G.
• Format: Text
• Language: English
• Published: 2018
• Subjects: envir; geo; ice core
• Online Access: https://doi.org/10.5194/cp-14-2071-2018; https://cp.copernicus.org/articles/14/2071/2018/

The Mid-Brunhes Transition (MBT) began ∼ 430 ka with an increase in the amplitude of the 100 kyr climate cycles of the past 800 000 years. The MBT has been identified in ice-core records, which indicate interglaciations became warmer with higher atmospheric CO2 levels after the MBT, and benthic oxygen isotope (δ18O) records, which suggest that post-MBT interglaciations had higher sea levels and warmer temperatures than pre-MBT interglaciations. It remains unclear, however, whether the MBT was a globally synchronous phenomenon that included other components of the climate system. Here, we further characterize changes in the climate system across the MBT through statistical analyses of ice-core and δ18O records as well as sea-surface temperature, benthic carbon isotope, and dust accumulation records. Our results demonstrate that the MBT was a global event with a significant increase in climate variance in most components of the climate system assessed here. However, our results indicate that the onset of high-amplitude variability in temperature, atmospheric CO2, and sea level at ∼430 ka was preceded by changes in the carbon cycle, ice sheets, and monsoon strength during Marine Isotope Stage (MIS) 14 and MIS 13.