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Extreme weather and climate events tend to increase and strengthen as global warming intensifies, which severely affect human life and sustainable economic development. Therefore, based on the Detection and Attribution Model Intercomparison Project (DAMIP) and the Land Use Model Intercomparison Project (LUMIP) provided by the Coupled Model Intercomparison Project phase 6 (CMIP6), the optimal fingerprinting method is applied to quantify the greenhouse gases (GHG), aerosols (AA), natural forcing (NAT), and land use/cover change (LUCC) contributions to the intensity, frequency, and duration of extreme temperatures in China during 1960—2020. The results show that GHG is the main driver of extreme temperature changes in China, except for ice days (ID0) and cold spells (CSDI). GHG causes an increase in warm spells (WSDI) by about 10 days and an extension of the growing season length (GSL) by 6 to 8 days. The Tibetan Plateau is the region with the strongest extreme temperature changes influenced by GHG. AA forcing has a cooling effect that partially offsets the warming effect of GHG, especially in southeastern China. It should be pointed out that AA forcing is also the main driver for the changes in diurnal temperature range (DTR) in southeastern China, which exceeds the GHG contribution. Additionally, LUCC has greater impact in nighttime extreme temperature indices changes than the regional AA, and becomes the second dominant factor beside GHG. LUCC leads to an attributable cooling contribution of 0.34 °C for the maximum of daily minimum temperatures (TNx). Spatially, the LUCC effects on extreme temperature changes are stronger in western China than in eastern China. The more robust estimation of the GHG, AA, NAT, and LUCC contributions over distinct regions provides an advanced understanding of anthropogenic impacts on regional extreme temperatures, which is expected to be an important reference for regional climate change adaptation and mitigation. [Display omitted] • Tibetan Plateau is the region with the strongest extreme temperature changes influenced by greenhouse gases (GHG). • GHG displays a nonuniformity effect on the changes in the extreme temperature frequency. • Land use/cover change (LUCC) has a stronger role in nighttime extreme temperature indices changes than the regional AA. • The LUCC effects on extreme temperature changes are stronger in western China than in eastern China • The LUCC effects on extreme temperature show asymmetrical characteristics. [ABSTRACT FROM AUTHOR]

Understanding future climate change is crucial for securing and managing water supplies necessary for agricultural activities in China, particularly in rainfed agriculture regions. This paper evaluates the projected climate change for nine major agricultural zones in China, using ensembles of regional climate models (RCMs) simulated under the Coordinated Regional Downscaling Experiment-East Asia second phase (CORDEX-EA-II) framework. The simulations were conducted for two climate scenarios (RCP2.6 and RCP8.5) at a 25 km grid spacing, with three RCMs (RegCM4, REMO, and WRF) driven by multiple CMIP5 global climate models (GCMs). The study compares the RCM simulations to the driving CMIP5 and the recent CMIP6 ensembles, focusing on surface temperature, precipitation, and surface relative humidity for the present day (1981–2010), mid-future (2036–2065), and far future (2070–2099) periods. The model evaluations indicate that the GCM and RCM simulations are consistent with observations, with RCMs showing better performance than the driving GCMs. The results show that both GCMs and RCMs project increased temperature and precipitation in most agricultural zones of China in the future, with the CMIP6 ensembles projecting the largest temperature increase and the CORDEX-EA-II ensemble showing the finest spatial details. Relative humidity is projected to decrease over major rice-producing areas of South China in the CORDEX-EA-II, CMIP5, and CMIP6 ensembles. This study provides valuable information to support climate change adaptation and mitigation efforts in China, particularly in the agricultural sectors. • CORDEX-EA-II simulations demonstrate better model performance over China. • Temperature and precipitation are projected to increase in the future. • Relative humidity is projected to decrease over South China. [ABSTRACT FROM AUTHOR]

In recent years, ozone pollution has attracted wide attention from the scientific community, policymakers and the public. Previous studies have already confirmed the effects of meteorological conditions on regional ozone pollution events in the last two decades. However, due to the lack of historical ozone observations, the relationship of climate variability and ozone pollution has been less discussed. In our study, we use the NCEP/NCAR Reanalysis data and modeled historical surface ozone from CMIP6 (Coupled Model Intercomparison Project Phase 6) to explore the impact of climate variability related to Tibetan Plateau on summertime (June, July and August) ozone in Central China during 1950–2019. The results show that in interdecadal timescale, the annual summertime ozone over Central China is significantly correlated (R = −0.52; P -value <0.05) with the springtime (March, April and May) thermal forcing, indicated by total atmospheric energy (TPE), over Tibetan Plateau. In high TPE years, the East Asian monsoon (southerly wind flow) and vertical ascending motion have been enhanced in summer. It is conducive to both the diffusion of ozone and its precursors and occurrence of cloudy and high humidity weather. These processes lead to lower ozone concentrations up to 6.97 ppb (compared with values averaged during 1950–2019) over Central China. On the contrary, in low TPE years, summertime surface ozone concentrations have been increased by 2.96 ppb (the mean value is 49.00 ppb and the standard deviation is 11.75 ppb for 1950–2019) on average of Central China, due to the weakened East Asian monsoon and weakened vertical ascent, thus the stable weather with low humidity and small near surface wind. After the year 2000, the TPE has increased with a rapid growth rate of 3 × 104 hPa J kg−1 yr−1. However, similar to the reported surface ozone increments based on the modeling results and observations, the CMIP6 summertime surface ozone has shown an increasing trend in the last two decades (0.45 ppb yr−1 and 0.25 ppb yr−1 over Central China and entire China during 1950–2019, respectively). While a decline trend (0.18 ppb yr−1) of ozone from 1980 to 2019 over Central China is calculated after the removal of emission-attributed trend. These results indicate that the ozone increasing trend dependent on the changes of precursor emissions has offset the ozone mitigation attributed to the climate. • Effect of springtime thermal forcing over TP on summertime ozone is revealed. • Thermal forcing over Tibetan Plateau has an interannual to decadal variation. • Historical weather over Asian monsoon region are affected by thermal forcing over TP. • Ozone increases due to emissions has offset the ozone mitigation due to the climate. [ABSTRACT FROM AUTHOR]