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Numerous studies, spanning experimental, instrumental, historical, and modeled approaches, have delved into understanding climate change across the Holocene era and millennial-scale occurrences. However, the chronology and causes of centennial-scale climate events during the Holocene remain controversial. In this study, we overviewed 10 of the best-resolved and most accurately dated records detailing climate change in the Northern Hemisphere (NH) over the Holocene, obtained from different proxies across different climatic zones, and constructed a stack of temperature changes in the NH. Based on the constructed stack, we identified and categorized 15 notable Holocene centennial cooling events (HCCEs) in the NH (period with temperature decreases). To test the chronological validity of the constructed HCCEs, we compared them with the most accurately dated and highly resolved climate records during the last 3 kyr, which have been extensively investigated by the scientific community. Based on the close alignment of the outlined HCCEs with temperature records, we suggest that other HCCEs also match centennial climate cooling events over the last 10 kyr. To understand the origins of the established HCCEs, we compared them with potential climate influencing factors: total solar irradiance (TSI), explosive volcanic activity, Atlantic meridional overturning circulation (AMOC)-limited slowdowns, Intertropical Convergence Zone (ITCZ) fluctuations, and El Niño/Southern Oscillation (ENSO variability. Early Holocene HCCE 5, terminated by a prominent 8.2-ka cold event, was likely driven by the superposition of the AMOC limited slowdown, TSI minimum, and volcanic activity. The Holocene Thermal Maximum (HTM) happened between HCCEs 5 and 4a and was interrupted by HCCE 4c and 4b, coeval, with a significant southward shift of the ITCZ, likely related to cooling in the tropical zone. However, the sequence of HCCEs 3b, 3a, and 2b (over 4.53–3.42 BP), accompanied by small changes in the TSI, was likely forced by an increase in ENSO variability, leading to remarkable changes in the tropical processes and a southward shift of the ITCZ, coeval with the collapse of the Chinese Neolithic cultures and onset of the Holocene Neoglacial. Subsequent HCCEs 2a–0a were likely forced by the TSI minimum combined with the influence of ENSO and volcanism over the last 2 ka. [ABSTRACT FROM AUTHOR]

Carbon dioxide capture, utilization and storage technology is considered to be one of the most effective strategies to mitigate CO2 emissions. In this process, CO2 that is injected into seabed sediments under specific temperature and pressure conditions is sealed in the form of CO2 hydrate, known for its high gas storage density and exceptional security features. This method has significant advantages compared with onshore geological storage schemes. Thus far, however, there has been no industrial demonstration of CO2 hydrate storage, and the CO2 hydrate storage potential in the South China Sea remains underexplored without targeted evaluations. In this study, the phase equilibrium mechanism is combined with the volumetric method to describe and evaluate the CO2 hydrate storage distribution range, effective thickness, and potential volume available for CO2 hydrate storage. Based on the latest exploration and development data from the Qiongdongnan Basin, along with geological structure data, multibeam bathymetry, local high-resolution three-dimension multichannel seismic reflection data, logging data, and submarine heat flow data, the distribution of the CO2 hydrate storage stability zone is determined. The results show that the effective thickness and regional scope of CO2 hydrate storage in the concerned area can be determined by virtue of the local water depths and the submarine temperature and pressure of 18 virtual wells. The minimum water depth in the Qiongdongnan Basin that satisfies the temperature and pressure conditions needed for CO2 sediment storage is established as 415 m. The theoretical geological storage capacity of CO2 hydrate in the Qiongdongnan Basin is determined as 5.75x1011 to 8.73x1011 t, where the value range of E is between 0.56 and 0.85. These findings offer a solid foundation for China to create, advance and execute a viable strategy for CO2 hydrate storage. [ABSTRACT FROM AUTHOR]

High resolution reconstructions based on productivity proxies and magnetic properties measured from sediment core 41-2 (off Kamchatka), reveal prevailing centennial-millennial productivity/climate variability in the northwestern (NW) Pacific from the Last Glacial Maximum (LGM) to the Early Holocene (EH). The core age model is established by AMS 14C dating using foraminifer shells from the core and by correlating the productivity cycles and relative paleomagnetic intensity records with those of well-dated nearby core, SO-201-12KL. Our results show a pronounced feature of centennial-millennial productivity/climate cycles of the NW Pacific had occurred synchronicity with the summer East Asian Monsoon (EAM) at sub-interstadial scale during the LGM (3 cycles), Heinrich Event 1(3 cycles), and Bølling/Allerød warming (4 cycles), and over the EH (3 cycles). Our comparison of the centennial-millennial variability to the Antarctic EDML (EPICA Dronning Maud Land) ice core suggests a "push" effect of Southern hemisphere temperature gradients on the summer EAM intensifications. Besides the linkages of NW Pacific high productivity and summer EAM, we observed that five low productivity cycles during EH are nearly synchronous with cooling in Greenland, weakening of the summer EAM, and decreases in solar irradiance. We propose that such centennial-millennial productivity/climate variability in the NW Pacific and sequence of sub-stadial/interstadials in the EAM from the LGM to EH are a persistent regional features, synchronous with the Greenland/North Atlantic short-term changes. We speculate that such climate synchronicity was forced also by changes in Atlantic meridional overturning circulation coupled with Intertropical Convergence Zone shifting and the northern westerly jets reorganization. [ABSTRACT FROM AUTHOR]