This study investigates the impact of vegetation–climate feedback on the global land monsoon system during the Last Interglacial (LIG, 127 000 years BP) and the mid-Holocene (MH, 6000 years BP) using the earth system model EC-Earth3. Our findings indicate that vegetation changes significantly influence the global monsoon area and precipitation patterns, especially in the North African and Indian monsoon regions. The North African monsoon region experienced the most substantial increase in vegetation during both the LIG and MH, resulting in significant increases in monsoonal precipitation by 9.8% and 6.0%, respectively. The vegetation feedback also intensified the Saharan Heat Low, strengthened monsoonal flows, and enhanced precipitation over the North African monsoon region. In contrast, the Indian monsoon region exhibited divergent responses to vegetation changes. During the LIG, precipitation in the Indian monsoon region decreased by 2.2%, while it increased by 1.6% during the MH. These differences highlight the complex and region-specific impacts of vegetation feedback on monsoon systems. Overall, this study demonstrates that vegetation feedback exerts distinct influences on the global monsoon during the MH and LIG. These findings highlight the importance of considering vegetation–climate feedback in understanding past monsoon variability and in predicting future climate change impacts on monsoon systems.

The East African uplift during the Miocene played a crucial role in reshaping regional climates, ecosystems, and faunal communities, contributing to a shift from forested landscapes to widespread grasslands. Here, we use the high-resolution Earth System Model EC-Earth3, coupled with a dynamic vegetation model, to simulate climate and vegetation responses to East African uplift across three key Miocene intervals (25, 20, and 15 Ma) under varying atmospheric CO₂ levels. Our results show that tectonic uplift, combined with declining CO₂ during the Middle Miocene Climate Transition, substantially reduced forest cover and promoted grassland expansion across East and Central Africa. These environmental transitions likely facilitated faunal dispersals and ecological turnover, including among large mammals and early crown hominoids. By integrating geodynamic reconstructions, paleoclimate modeling, and fossil data, this study provides insight into how large-scale Earth system processes shaped Miocene biodiversity and altered the environmental context for mammalian evolution in Africa.

Precipitation variability in the South African Monsoon Domain, which encompasses much of southern Africa and the adjoining Indian Ocean, is marked by a distinct dipole pattern, with one center over southeastern Africa and the other along a northwest-southeast-oriented belt that extends across tropical eastern Africa and the southwest Indian Ocean. However, the climatic mechanisms of this dipole pattern over timescales remain unclear. In this study, we integrate modern observations, reanalysis data, and regional paleoclimate proxy records spanning the past 8 ka to investigate hydroclimate variability in the eastern South African Monsoon Domain at interannual to millennial scales. While modern observations identify the Indian Ocean Basin Mode (IOB), Subtropical Indian Ocean Dipole (SIOD), and Indian Ocean Dipole (IOD) as key drivers, the shift from IOD- to IOB/SIOD-dominated SSTA patterns reflects both long-term Pacific forcing and strong Indian Ocean-Pacific coupling that critically shapes rainfall variability in the South African Monsoon Domain. The SIOD and IOB dominate hydroclimate fluctuations in tropical eastern Africa and the southwest Indian Ocean, while the interaction between SIOD and El Niño Southern Oscillation amplifies the southeastern Africa - the southwest Indian Ocean dipole pattern. On longer timescales, we find that multi-millennial and multi-centennial hydroclimate precipitation patterns broadly resemble the dipole pattern as observed today. However, comparisons lack support from western Indian Ocean SST reconstructions, necessitating further high-resolution SST records and model simulations to validate these relationships.

El Niño–Southern Oscillation (ENSO) events, whether in warm or cold phases, that persist for two or more consecutive years (multi-year), are relatively rare. Compared with single-year events, they create cumulative impacts and are linked to extended periods of extreme weather worldwide. Here we combine central Pacific fossil coral oxygen isotope reconstructions with a multimodel ensemble of transient Holocene global climate simulations to investigate the multi-year ENSO evolution during the Holocene (beginning ~11,700 years ago), when the global climate was relatively stable and driven mainly by seasonal insolation. We find that, over the past ~7,000 years, in proxies the ratio of multi-year to single-year ENSO events increased by a factor of 5, associated with a longer ENSO period (from 3.5 to 4.1 years). This change is verified qualitatively by a subset of model simulations with a more realistic representation of ENSO periodicity. More frequent multi-year ENSO events and prolonged ENSO periods are being caused by a shallower thermocline and stronger upper-ocean stratification in the Tropical Eastern Pacific in the present day. The sensitivity of the ENSO duration to orbital forcing signals the urgency of minimizing other anthropogenic influence that may accelerate this long-term trend towards more persistent ENSO damages.

Indian summer monsoon (ISM) change under global warming is a serious concern because of its widespread socio-economic impacts. Under the greenhouse gas (GHG)-induced near future warming, climate models project a weakened ISM circulation, limiting the rate of monsoon rainfall increase. However, we find that climate models commonly simulate a strengthened ISM circulation in favor of ISM rainfall increase during the mid-Pliocene that is often considered analogous to the ongoing anthropogenic warming. This enhanced ISM circulation change is physically consistent with a dramatically strong warming over Eastern Eurasia, which strengthened the mid-upper tropospheric meridional temperature gradient across the ISM region. Sensitivity experiments reveal that such an Eastern Eurasian warming was closely associated with the northern continental greening via local vegetation-albedo feedback. Our results highlight that the land cover changes, rather than GHG forcing, dominated this regional-scale warming and resultant regional hydrological cycle in the mid-Pliocene warm period.

The Earth's ice sheets, including the Antarctic Ice Sheet (AIS), are critical tipping points in the climate system. In recent years, the potential future collapse has garnered increased attention due to its cascading effects, which could significantly alter global climate patterns and cause large-scale, long-lasting, and potentially irreversible changes within human timescales. This study investigates the large-scale response of the polar Southern Hemisphere (pSH; comprising the Southern Ocean and Antarctica (60–90° S)) to the geometric reduction in ice sheets to a reconstructed Late Pliocene (LP) extent and imposing increased greenhouse gas (GHG) forcing in the Earth System. Using the PRISM4D reconstruction, where ice sheets such as the West Antarctic Ice Sheet (WAIS) were significantly diminished, we conducted multi-centennial simulations with the EC-Earth3 model at atmospheric CO₂ concentrations of 280 and 400 ppmv. The simulation performed with LP ice sheet extent leads to a 9.5 °C rise in surface air temperature, approximately a 16 % reduction in sea ice concentration (SIC) over Antarctica and the Southern Ocean. These changes far exceed those driven by CO₂ increase alone, which result in a 2.5 °C warming and a 9.3 % sea ice decline. Additionally, both experiments deduce there is a reversal in sea level pressure (SLP) polarity with respect to pre-industrial (PI) patterns. Higher-than-normal SLP is present over Antarctica, and lower-than-normal SLP is present in the mid-latitudes, indicative of a negative phase of the Southern Annular Mode (SAM). This is supported by a weakening of the westerly jet, which in turn contributes to the formation of a fresh cap in the upper ocean, induced by the imposed climatic impacts of our sensitivity experiments. This overall freshening of the upper ocean increases stratification in the water column and prevents deep convection in the Southern Ocean, thus leading to the formation of the Antarctic Bottom Water (AABW), which is paramount for the ventilation of the global ocean. Overall, our findings suggest that, by increasing the atmospheric concentration of CO₂, the AABW is suppressed at a multi-centennial timescale; however, by reducing the ice sheet extent, compensatory mechanisms, involving an extensive salinisation of the ocean interior, trigger partial recovery of this water mass. This emphasises the non-linearity of the climate system, since consequences of reducing the ice sheets induce an amplified warming and freshening in the near-surface, whereas they induce opposing mechanisms in the deep ocean that significantly alter the dynamics of water masses that feed the AABW. By isolating the climatic response to ice sheet extent reduction, whilst holding other parameters fixed, this study offers critical insights into the mechanisms driving atmospheric and oceanic variability around Antarctica and their broader implications for global climate dynamics. Here we provide a unique, targeted approach, specifically focusing on the direct impact of ice sheet retreat on regional climate.

The Miocene epoch, marked by significant tectonic and climatic shifts, presents a unique period to study the evolution of South Asian summer monsoon (SASM) dynamics. Previous studies have shown conflicting evidence: wind proxies from the western Arabian Sea suggest a weaker Somali Jet during the Middle Miocene compared to the Late Miocene, while rain-related records indicate increased SASM rainfall. This apparent decoupling of monsoonal winds and rainfall has challenged our understanding of SASM variability. Here, using the fully coupled EC-Earth3 model, we identify a key driver of this decoupling: changes in African topography rather than other external forcings such as CO₂ change. Our simulations reveal that changes in Miocene African topography weakened the cross-equatorial Somali Jet and reduced upwelling in the western Arabian Sea, while simultaneously enhancing monsoonal rainfall by inducing atmospheric circulation anomalies over the Arabian Sea. The weakened Somali Jet fostered a positive Indian Ocean Dipole-like warming pattern, further amplifying the monsoonal rainfall through ocean-atmosphere feedbacks. In contrast, CO₂ forcing enhances both Somali Jet and rainfall simultaneously, showing no decoupling effect. These findings reconcile the discrepancies between wind and rainfall proxies and highlight the critical role of African topography in shaping the multi-stage evolution of the SASM system.

Proxy data for eastern North American hydroclimate indicate strong and persistent multi-millennial droughts during the Holocene, but climate model simulations often fail to reproduce the proxy-inferred droughts. Diagnosing the data–model mismatch can offer valuable insights about the drivers of hydrological variability and different regional sensitivities to hydroclimate forcing. Here we present a proxy–modeling synthesis for Holocene climates in the eastern North American mid-latitudes, including machine-learning-based water balance reconstructions and high-resolution climate simulations. These data-model results resolve prior-generation inconsistencies, show consistent spatiotemporal patterns of Holocene hydroclimate change, and enable assessment of the driving mechanisms. This agreement suggests that the secular summer insolation trend, combined with the Laurentide Ice Sheet deglaciation and its effect on atmospheric circulation, together explain the extent and duration of drier-than-present climates. In addition, our high-resolution proxy data and transient simulations reveal clear multi-centennial climate variability. In our simulations, temperature-driven increases in evapotranspiration exceed regional precipitation gains, drying much of the region during the mid Holocene. This suggests that the mid-Holocene multi-millennial drought was driven by similar processes compared to the drying trajectory projected for mid-latitude North America over this century, which is also primarily driven by warming.

Understanding multidecadal to centennial-scale climate variability in arid Central Asia remains challenging due to limitations in the age control, resolution, and duration of available proxy records. In this study, we analyzed a continuous, and precisely dated (∼6 ‰ precision) stalagmite δ¹⁸O record with high temporal resolution (∼4 years) that spans the mid- to late Holocene from Talisman cave in the Fergana Valley, Kyrgyzstan, in arid Central Asia (ACA). This record reveals significant climate variability at both multidecadal and centennial timescales. Spectral analysis suggests that these fluctuations may be linked to solar forcing and the North Atlantic Oscillation (NAO). Drier conditions appear to coincide with a northward shift of the Westerlies, which in turn may be driven by reduced solar activity and positive phases of the NAO. Notably, multidecadal δ¹⁸O fluctuations, coincided with the NGRIP δ¹⁸O record and the Atlantic Meridional Overturning Circulation (AMOC) index, slightly weakened during major ice-rafted debris (IRD) events—likely due to freshwater forcing and internal atmospheric variability.

Multiple tipping points in the Earth system could be triggered when global warming exceeds specific thresholds. However, the degree of their impact on the East Asian hydroclimate remains uncertain due to the lack of quantitative rainfall records. Here we present an ensemble reconstruction of East Asian summer monsoon (EASM) rainfall since the Last Glacial Maximum (LGM) using nine statistical and machine learning methods based on multi-proxy records from a maar lake in southern China. Our results define five tipping points in the EASM rainfall since the LGM, which are characterized by abrupt and irreversible regime shifts with a median amplitude of 387 ± 73 mm (24 ± 5 %). Combined with multi-model simulations and existing records, we attribute these tipping points to cascades of abrupt shifts in the Atlantic meridional overturning circulation (AMOC) and Saharan vegetation. Our findings underscore the nonlinear behavior of the EASM and its coupling with other tipping elements.