The paleoclimatic sensitivity to atmospheric greenhouse gases (GHGs) has recently been suggested to be nonlinear, however a GHG threshold value associated with deglaciation remains uncertain. Here, we combine a new sea surface temperature record spanning the last 360,000 years from the southern Western Pacific Warm Pool with records from five previous studies in the equatorial Pacific to document the nonlinear relationship between climatic sensitivity and GHG levels over the past four glacial/interglacial cycles. The sensitivity of the responses to GHG concentrations rises dramatically by a factor of 2–4 at atmospheric CO₂ levels of >220 ppm. Our results suggest that the equatorial Pacific acts as a nonlinear amplifier that allows global climate to transition from deglacial to full interglacial conditions once atmospheric CO₂ levels reach threshold levels.

The low-cost and easy-to-use nature of rapidly developed PM_2.5 sensors provide an opportunity to bring breakthroughs in PM_2.5 research to resource-limited countries in Southeast Asia (SEA). This review provides an evaluation of the currently available literature and identifies research priorities in applying low-cost sensors (LCS) in PM_2.5 environmental and health research in SEA. The research priority is an outcome of a series of participatory workshops under the umbrella of the International Global Atmospheric Chemistry Project–Monsoon Asia and Oceania Networking Group (IGAC–MANGO). A literature review and research prioritization are conducted with a transdisciplinary perspective of providing useful scientific evidence in assisting authorities in formulating targeted strategies to reduce severe PM_2.5 pollution and health risks in this region. The PM_2.5 research gaps that could be filled by LCS application are identified in five categories: source evaluation, especially for the distinctive sources in the SEA countries; hot spot investigation; peak exposure assessment; exposure–health evaluation on acute health impacts; and short-term standards. The affordability of LCS, methodology transferability, international collaboration, and stakeholder engagement are keys to success in such transdisciplinary PM_2.5 research. Unique contributions to the international science community and challenges with LCS application in PM_2.5 research in SEA are also discussed.

The variability of the northern westerlies has been considered as one of the key elements for modern and past climate evolution. Their multiscale behavior and underlying control mechanisms, however, are incompletely understood, owing to the complex dynamics of Atlantic sea-level pressures. Here, we present a multi-annually resolved record of the westerly drift over the past 6,500 years from northern Italy. In combination with more than 20 other westerly-sensitive records, our results depict the non-stationary westerly-affected regions over mainland Europe on multi-decadal to multi-centennial time scales, showing that the direction of the westerlies has changed with respect to the migrations of the North Atlantic centers of action since the middle Holocene. Our findings suggest the crucial role of the migrations of the North Atlantic dipole in modulating the westerly-affected domain over Europe, possibly modulated by Atlantic Ocean variability.

The Kuroshio intrusion (KI) is a northwestward‐flowing branch of the Kuroshio Current, which enters the South China Sea (SCS) and regulates its temperature, salinity, and water mass exchanges. However, limited direct observations hinder our understanding of KI's mechanisms and responses to climate change. Here, we present a 60‐year bi‐monthly resolved coral oxygen isotope (δ¹⁸Oc) record from Dongsha Atoll, the northern SCS. The dry‐season (December–March) δ¹⁸Oc record reveals interannual to decadal variabilities of the KI. The impact of the East Asian winter monsoon (EAWM) on Dongsha δ¹⁸Oc was more pronounced during the 1970s and 1980s and after the early 2000s, while the influence of the El Niño‐Southern Oscillation (ENSO) on Dongsha δ¹⁸Oc was higher between the 1980s and 1990s. The Pacific Decadal Oscillation (PDO) may have a relatively minor effect on KI strength or may indirectly modulate KI strength through its influence on ENSO activities. Our Dongsha δ¹⁸Oc record highlight the importance of the EAWM, ENSO, and PDO in predicting future KI changes.

The May and June precipitation (known as early summer precipitation; ESP) is an important water resource for South China and Taiwan (SCTW). This study explores the similarities and differences between the Community Earth System Model Version 2‐Large Ensemble (CESM2‐LE) and the Coupled Model Intercomparison Project Phase 6 (CMIP6) multi‐model ensemble in simulating the characteristics of ESP over SCTW in the present day, and in projecting the related changes at the end of 21st century. For the present‐day simulation, our results showed that CESM2‐LE and CMIP6 outperformed each other for different examined features. CESM2‐LE was slightly better than CMIP6 in capturing the magnitude of ESP over SCTW, while CMIP6 was more capable of representing the interdecadal shifts in the occurrence timing of the ESP maximum. Both the CESM2‐LE and CMIP6 projections indicated that ESP will be enhanced and the phase of maximum ESP will be delayed, from peaking around mid‐June in the present to late June in the future. These changes can be attributed to an enhanced short‐wave trough over southwest China and a late intensification of the southwesterly wind ahead of the short‐wave trough, which help transport more moisture from the north of the South China Sea to SCTW, particularly in mid‐to‐late June. In addition, relative to CMIP6, CESM2‐LE showed less uncertainty in the projected increase in ESP and phase delay. This finding highlights that model diversity may play a more important role than internal variability in attributing the uncertainty of projected changes in ESP over SCTW.

The Asian Monsoonal rainfall accounts for the majority of annual regional precipitation in East and South Asia and could be remotely regulated by El Niño‐Southern Oscillation (ENSO). Besides, several paleoclimate records and simulations have indicated solar signals in the Asian Monsoon, implying the impact of solar activity on the regional monsoon precipitation. By conducting multi‐linear regression analysis to the solar irradiance forced single‐forcing experiment in the last millennium, this study presents the comparison of solar and ENSO effects on monsoonal precipitation in South and East Asia during early summer (May–June). Increased total solar irradiance during high solar activity years tends to trigger a favorable environment for developing monsoon onset, leading to more precipitation against ENSO‐related patterns over Southeast and South Asia before peak‐summer (July–August). The result supports reconstructed terrestrial records and underlines considerable influences of the solar cycle on the variation of the Asian Summer Monsoon.