Meltwater Pulses (MWPs) from the last deglaciation are highly relevant today. Studying their timing and characteristics offers valuable insights into past periods of accelerated sea-level response under intense climate forcing and provides an analog for potential future scenarios. The western Bohai Sea coast (WBSC), located deep within the Asian continent and far from major glaciation centers and subduction zones, exhibits sensitive relative sea level (RSL) responses to any high latitude ice-sheet meltwater influx, offering valuable data to refine the chronology and magnitude of MWPs. This paper presents 25 high-confidence early Holocene sea-level index points (SLIPs) from high marsh vegetation samples, generated through analysis of sediments, microfossil foraminifera, and radiocarbon dating of 14 cores from the WBSC. The altitudes of SLIPs were adjusted for factors such as self-compaction, long-term tectonic subsidence, and ground lowering due to water extraction. The early Holocene RSL history in the WBSC reflects a rapid rise in sea level during ∼9800–6900 cal a BP, occurring within the global context of global sea-level rise. During ∼9800–8100 cal a BP, the RSL rise was faster, averaging 7–8 mm/a, characterized by two distinct stepwise increases. A rapid sea-level rise event before 9500 cal a BP was shown by a sharp RSL rise of at least 5.4 ± 0.63 m, within the narrow timeframe of 9603 ± 288 cal a BP (1σ). The second MWP took place during 8500–8100 cal a BP, adding a total rise of 2.92 ± 0.93 m on the top of background RSL rise, with a two-phase structure where the main phase produced 2.55 ± 0.69 m within a narrow window around 8505 ± 135 cal BP (1σ). Although the rate of RSL rise decreased rapidly to 5.0 mm/a by 7000 cal a BP after ∼8100 cal a BP, sea-level data from the WBSC still show an additional rise of 1.45 ± 0.64 m during 7593 ± 78 cal a BP (1σ). These three distinct sea-level jump events, happened before 9500, ∼8500, and ∼7600 cal a BP, respectively, provide indications of three episodes of enhanced meltwater discharge in the early Holocene, with the latter two closely linked to the decaying history of the Laurentide Ice Sheet.

The Bohai Sea, located in the innermost part of the East Asian marginal seas, is of particular interest in the studies of relative sea level (RSL) and glacial isostatic adjustment (GIA) due to its apparent far-field position. This study analyzed six cores and one pre-existing archaeological site from the southern Bohai Sea coast, generating 11 sea-level index points (SLIPs) from supratidal, upper tidal, and mid-lower tidal flat sediments using foraminifera tests and sedimentary analysis. All SLIPs were corrected for possible self-compaction, long-term tectonic effect, and the lowering effect due to water extraction. This enabled a high-quality reconstruction of RSL changes over the age range of 9000–3000 cal a BP. The RSL rose rapidly from about −17.19 ± 1.32 m to 1.76 ± 1.32 m MSL between around 9000 and 7000 cal a BP. However, the RSL rise rates quickly decreased from around 8–10 mm/a before 8000 cal a BP to ∼4mm/a by 7000 cal a BP. After 7000 cal a BP, the RSL continued to rise, reaching its peak of 2.44 ± 1.34 m MSL around 6000 cal a BP followed by a gradual decline to the present height at 3000–4000 cal a BP, with a maximum falling rate of 1.2 mm/a around 5000 cal a BP. Comparisons of the reconstructed RSL in this study with those from other non-deltaic regions, including the inner Hangzhou Bay and the surrounding coasts of western Bohai Sea, as well as with GIA predictions by ICE6G, ANU, and region-specific ‘final model’ reveal: (1) a significant and long-term early-to-mid Holocene continental levering effect on the southern Bohai Sea coast; (2) a close fit with the region-specific ‘final model’, albeit with SLIPs that fall slightly below predictions from 9000 to 8000 cal a BP and form a distinct mid-Holocene highstand above model projections after 7000 cal a BP; (3) these data-model misfits may result, in the former case, from the GIA model's Holocene ice melting history not embedding accelerated sea-level rise events, and in the latter, from the presence of a relatively strong upper mantle at the southern Bohai Sea coast, rather than the extremely weak upper mantle assumed for the Bohai Sea region.