Extreme high‐temperature events have large socioeconomic and human health impacts. East Asia (EA) is a populous region, and it is crucial to assess the changes in extreme high‐temperature events in this region under different climate change scenarios. The Community Earth System Model low‐warming experiment data were applied to investigate the changes in the mean and extreme high temperatures in EA under 1.5°C and 2°C warming conditions above preindustrial levels. The results show that the magnitude of warming in EA is approximately 0.2°C higher than the global mean. Most populous subregions, including eastern China, the Korean Peninsula, and Japan, will see more intense, more frequent, and longer‐lasting extreme temperature events under 1.5°C and 2°C warming. The 0.5°C lower warming will help avoid 35%–46% of the increases in extreme high‐temperature events in terms of intensity, frequency, and duration in EA with maximal avoidance values (37%–49%) occurring in Mongolia. Thus, it is beneficial for EA to limit the warming target to 1.5°C rather than 2°C.

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With anthropogenic global warming, heat‐related extreme events are projected to increase in severity and frequency. Already vulnerable regions like Africa will be hard‐hit. Therefore, such regions could benefit from low global warming levels. Using the Community Earth System Model low warming simulations, we investigate changes in temperature extremes across Africa as a function of global mean temperature in the context of the implications of the Paris Agreement's targets. A significant warming across Africa is projected at the 1.5 °C warming world and is amplified at the 2 °C world, exceeding the mean global warming rate. Specifically, North Africa and East Africa regions are projected to have the highest and lowest temperature changes of 0.63 °C (0.60–0.67 °C) and 0.50 °C (0.47–0.54 °C), respectively, between the 1.5 and 2 °C warmer worlds. Consequently, hot events are also estimated to increase with global warming. We showed that limiting warming to 1.5 °C instead of 2 °C may lead to 29% (27–31%) to 35% (33–37%) reduction in severity of hot events and to 31% (30–33%) to 42% (39–48%) reduction in the frequency of the threshold‐based high‐temperature events across Africa. The highest reductions are projected over North Africa. Furthermore, restricting warming to 0.5 °C lower than 2 °C might also result in 28% (34–40%) to 37% (25–34%) reduction in severity of once‐in‐10/20‐year heat events across Africa with North Africa having the highest benefits than tropical regions. Thus, restricting warming to low levels may indeed translate to substantial benefits of reduced intensity and frequency of extreme heat events across Africa.

An anomalous South Asian summer monsoon (SASM) system could generate a large anomaly in precipitation and hydrological disasters in the SASM-prevailing area, as widely reported for the Indian Peninsula. However, how the SASM system influences the precipitation anomaly over the South-Central Tibetan Plateau (SCTP) is largely unknown. In this study, we (a) analyze the influences of the early and late onset (demise) of the SASM on the interannual variations in precipitation over the SCTP during 1979–2015; and (b) illuminate the underlying mechanisms and asymmetric effects with regard to the onset and demise of the SASM by analyzing the characteristics of water vapor transport and moisture budgets in this region. Results indicate that the precipitation anomaly over the SCTP is dominated by the cyclonic and anticyclonic water vapor transport associated with the anomalous SASM activities, causing moisture convergence and divergence in this region. The topographic effect in the southeastern Tibetan Plateau (SETP) and southwestern Tibetan Plateau (SWTP) further strengthens the anomaly in water vapor transport in vertical direction and contributes to the precipitation anomaly through moisture convergence and divergence. The anomalous SASM and topography exhibit asymmetric effects between the onset and demise as well as between the early and late onset (demise) of the SASM. They cause 23.41%, 15.91%, and 1.96% difference in precipitation between the early and late SASM-onset years, and 13.05%, 21.50%, and 29.86% difference in precipitation between the early and late SASM-demise years in the SETP, central Tibetan Plateau (CETP), and SWTP, by regulating the horizontal and vertical thermodynamic and dynamic processes. The results help improve our understanding of the SASM-precipitation relationship over the SCTP and guide the prediction of precipitation and alleviation of water-related disasters in the region and its surroundings that are home to billions of people in Asia.

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This study compared statistical downscaling model (SD) and dynamical downscaling model (DD) for changes in extreme temperature and precipitation indices, driven by the same global climate model output, in the 1.5 and 2 °C warmer climates in China. Simple bias correction (BC) methods were used to correct the climatology of temperature and precipitation in both models. After BC, both models show comparable performance in reproducing the spatial distributions of the extreme temperature and precipitation indices. Corrected model data were used to analyze future changes. Changing patterns of the extreme temperature indices are similar in the two models. Compared with the 2 °C warmer climate, warming 0.5 °C less can help reduce about 6% of summer day (SU) and 11% of tropical night (TR) increases (relative to 1986–2005) in China. Specifically, the reduced values of TR in northwest and northeast China are larger than 30% and 70%, respectively, in both models. Extreme wet indices will increase in most parts of China in the warmer climates. In DD, 5‐day maximum precipitation (RX5day) will increase by approximately 10% and 14% in the 1.5 and 2 °C warmer climates, respectively, with maximal values (17% and 28%, respectively) occurring in north China. In SD, differences in extreme wet indices between the two warmer climates are small, and RX5day will increase more than 20% in northeast China. In DD, specific humidity will increase, and the East Asian summer monsoon will be enhanced in the warmer climates, favoring a larger increase in wet extremes in north China compared to other parts of east China.

Highly populated East Asia is vulnerable to extreme precipitation. Here, we use Community Earth System Model low-warming simulations to examine how extreme precipitation events may change in East Asia under the Paris Agreement global warming targets. The frequency and intensity of extreme precipitation will increase markedly over East Asia in the warmer climates. Limiting end-of-century warming to 1.5°C, in comparison with 2°C, will reduce the risks of extreme precipitation frequency and intensity in East Asia by 26%-31%, with the greatest reductions (38%-54%) in Japan. A brief overshoot of the 1.5°C target would affect Mongolia, the Korean Peninsula and Japan from the aspects of regional average. More than 25% of the increase in the frequency and intensity of extreme precipitation in these regions can be avoided during the end of the 21st century (2081-2100) if there is no temperature overshoot, according to the best estimate. Vertical moisture advection is the main contributor to changes in precipitation-minus-evaporation in East Asia in the warmer climates. The increased low-level specific humidity and cyclonic circulation changes are the dominant thermodynamic and dynamical processes that contribute to the increase of precipitation over South China and Japan. Our work suggests that limiting warming to 1.5°C without overshoot is beneficial to minimizing the impacts associated with precipitation extremes across East Asia.

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