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.

Increasing surface air temperature is a fundamental characteristic of a warming world. Rising temperatures have potential impacts on human health through heat stress. One heat stress metric is the wet-bulb globe temperature, which takes into consideration the effects of radiation, humidity, and wind speed. It also has broad health and environmental implications. This study presents wet-bulb globe temperatures calculated from the fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis and combines it with health guidelines to assess heat stress variability and the potential for reduction in labor hours over the past decade on both the continental and urban scale. Compared to 2010–2014, there was a general increase in heat stress during the period from 2015 to 2019 throughout the northern hemisphere, with the largest warming found in tropical regions, especially in the northern part of the Indian Peninsula. On the urban scale, our results suggest that heat stress might have led to a reduction in labor hours by up to ~20% in some Asian cities subject to work–rest regulations. Extremes in heat stress can be explained by changes in radiation and circulation. The resultant threat is highest in developing countries in tropical areas where workers often have limited legal protection and healthcare. The effect of heat stress exposure is therefore a collective challenge with environmental, economic, and social implications.

The effect of climate prevails on a diverse time scale from days to seasons and decades. Between 1993 and 2013, global warming appeared to have paused even though there was an increase in atmospheric greenhouse gases. The variations in oceanographic variables, like current speed and sea surface temperature (SST), under the influence of the global warming hiatus (1993–2013), have drawn the attention of the global research community. However, the magnitude of ocean current and SST characteristics oscillates and varies with their geographic locations. Consequently, investigating the spatio-temporal changing aspects of oceanographic parameters in the backdrop of climate change is essential, specifically in coastal regions along Kuroshio current (KC), where fisheries are predominant. This study analyzes the trend of ocean current and SST induced mainly during the global warming hiatus, before and till the recent time based on the daily ocean current data from 1993 to 2020 and SST between 1982 and 2020. The Kuroshio extent is delineated from its surrounding water masses using an aggregation of raster classification, stretching, equalization, and spatial filters such as edge detection, convolution, and Laplacian. Finally, on the extracted Kuroshio extent, analyses such as time series decomposition (additive) and statistical trend computation methods (Yue and Wang trend test and Theil–Sen’s slope estimator) were applied to dissect and investigate the situations. An interesting downward trend is observed in the KC between the East coast of Taiwan and Tokara Strait (Tau = −0.05, S = −2430, Sen’s slope = −5.19 × 10−5, and Z = −2.61), whereas an upward trend from Tokara Strait to Nagoya (Tau = 0.89, S = 4344, Sen’s slope = 8.4 × 10−5, and Z = 2.56). In contrast, a consistent increasing SST in trend is visualized in the southern and mid-KC sections but with varying magnitude.

While there have been many paleoclimate studies on the precessional control of climate, typically only the orbital phase where perihelion occurs close to the solstices has received attention. Here, we explore how precession affects the seasonal evolution of the Asian summer monsoon in the transitional seasons of boreal spring and autumn. With perihelion occurring in boreal spring, the Hadley circulation weakens over the northern Indian Ocean, linked to precession-enhanced sensible heating over the Tibetan Plateau. There is an early northward migration of the midlatitude westerly jet stream, and the advancement of the pre-monsoon along the Asian–Australian land bridge. The pre-monsoon response to precession may have had a major role in the early part of the last deglaciation, when perihelion last occurred during boreal spring. A weak continental summer monsoon and autumn aphelion during the early part of the last deglaciation led to a weak Pacific high over the east of coastal East Asia, allowing for a vigorous oceanic western North Pacific monsoon in the late summer. Additionally, the seasonal expansion of oceanic monsoon trough could shed light on the quasi-stationarity of the oceanic monsoon during a precessional cycle.

The impacts of anthropogenic forcing on Indian summer monsoon (ISM) rainfall are obscure, partly due to limited availability of highly resolved hydroclimate proxy records as well as the highly regionalized nature of precipitation. Here, we report an annually‐resolved speleothem oxygen isotope record from Xianren Cave, southwestern China, which represents rainfall change over the broad ISM region. We find that the region has endured at least six decadal‐scale weak monsoon events in the past three hundred years. One of them, lasting from the early to mid 19th century, shares the similar gradual, persistent trend as the most recent decline in ISM rainfall and both have a magnitude substantially larger than the others dominated by natural variability. This early weak monsoon event occurred during a historical time of intensive deforestation in the region. We conclude that the ISM trend could have been altered by the changes in land‐use and land‐cover since the early 19th century.