Climate evolution across the Mid-Brunhes Transition

• Main Authors: A. M. Barth, P. U. Clark, N. S. Bill, F. He, N. G. Pisias
• Format: Article
• Language: English
• Published: Copernicus Publications 2018-12-01
• Series: Climate of the Past
• Online Access: https://www.clim-past.net/14/2071/2018/cp-14-2071-2018.pdf

<p>The Mid-Brunhes Transition (MBT) began <span class="inline-formula">∼</span>&thinsp;430&thinsp;ka with an increase in the amplitude of the 100&thinsp;kyr climate cycles of the past 800&thinsp;000 years. The MBT has been identified in ice-core records, which indicate interglaciations became warmer with higher atmospheric <span class="inline-formula">CO₂</span> levels after the MBT, and benthic oxygen isotope (<span class="inline-formula"><i>δ</i>¹⁸O</span>) 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 <span class="inline-formula"><i>δ</i>¹⁸O</span> 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 <span class="inline-formula">CO₂</span>, and sea level at <span class="inline-formula">∼430</span>&thinsp;ka was preceded by changes in the carbon cycle, ice sheets, and monsoon strength during Marine Isotope Stage (MIS) 14 and MIS 13.</p>