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Many agricultural regions in China are likely to become appreciably wetter or drier as the global climate warming increases. However, the impact of these climate change patterns on the intensity of soil greenhouse gas (GHG) emissions (GHGI, GHG emissions per unit of crop yield) has not yet been rigorously assessed. By integrating an improved agricultural ecosystem model and a meta‐analysis of multiple field studies, we found that climate change is expected to cause a 20.0% crop yield loss, while stimulating soil GHG emissions by 12.2% between 2061 and 2090 in China's agricultural regions. A wetter‐warmer (WW) climate would adversely impact crop yield on an equal basis and lead to a 1.8‐fold‐ increase in GHG emissions relative to those in a drier‐warmer (DW) climate. Without water limitation/excess, extreme heat (an increase of more than 1.5°C in average temperature) during the growing season would amplify 15.7% more yield while simultaneously elevating GHG emissions by 42.5% compared to an increase of below 1.5°C. However, when coupled with extreme drought, it would aggravate crop yield loss by 61.8% without reducing the corresponding GHG emissions. Furthermore, the emission intensity in an extreme WW climate would increase by 22.6% compared to an extreme DW climate. Under this intense WW climate, the use of nitrogen fertilizer would lead to a 37.9% increase in soil GHG emissions without necessarily gaining a corresponding yield advantage compared to a DW climate. These findings suggest that the threat of a wetter‐warmer world to efforts to reduce GHG emissions intensity may be as great as or even greater than that of a drier‐warmer world. Plain Language Summary: Both climate observations and projections suggest that warmer temperatures will intensify convective precipitation, resulting in drier regions becoming drier and wetter regions becoming wetter. By integrating an improved agricultural ecosystem model and a meta‐analysis of multiple field studies, this study has investigated the effects of drier‐warmer (DW) and wetter‐warmer (WW) climates on crop yield and soil greenhouse gas emissions in China. Our findings indicate that the cost of greenhouse gas emissions in a wetter‐warmer world for crop production could be as high as or even higher than in a drier‐warmer world. Moreover, this study suggests that effective climate mitigation practices need to account for the combined effects of extreme climate changes and nitrogen addition on greenhouse gas emissions and crop production. Therefore, China would need to exert considerably more effort in a future with warmer and wetter conditions to achieve its greenhouse gas emission reduction targets. Key Points: Climate change would cause a 20% crop yield loss and an increase of 12.2% in soil greenhouse gas (GHG) emissions between 2061 and 2090A Wetter‐Warmer climate would cause a more significant crop yield loss and about double the GHG emissions of a Drier‐Warmer climateNitrogen fertilizer‐induced GHG emissions in a Wetter‐Warmer climate would increase 37.9% compared to those in a Drier‐Warmer climate [ABSTRACT FROM AUTHOR]

Concurrent hot extremes and droughts undoubtedly aggravate the impacts of droughts on agriculture, natural environment, and human society. Recent studies mainly focus on the trends and changes in frequency and severity of compound drought and hot extreme events. However, relatively little attention has been paid to the changes in mean temperature during drought conditions. In this study, we investigated the mean temperature changes during droughts in observed and projected periods across China on a century time‐scale and explored the possible contributions of land surface‐atmosphere interactions or atmospheric moisture conditions to these changes. China experienced reduced rather than amplified warming under droughts both in observations and future projections. A drier condition or a higher emission scenario was projected to result in a larger range of mean temperature changes under droughts in the future. We attributed the reduced mean temperatures under droughts to increasing winter droughts and higher atmospheric moisture conditions. This study provides a reference for water resource management, drought risk reduction, as well as mitigation of agricultural crop loss and public health damage. Plain Language Summary: Previous climate studies generally focus on the trend analysis of concurrent droughts and hot extremes, especially in summer. There are gaps in our knowledge on how does the mean temperature under droughts change under climate warming, and what are the underlying driving factors? We investigated the changes in mean temperature during droughts across China using monthly observed data and projected data. China experienced reduced rather than amplified warming under droughts both in observations and future projections. A drier condition or a higher emission scenario could result in a larger range of mean temperature changes under droughts in the future. Increasing winter droughts and higher atmospheric moisture conditions resulted in the reduced mean temperatures under droughts. Our study provides references for policymakers to inform water resource management, drought risk reduction, and mitigation of agricultural crop loss. Key Points: China experienced reduced rather than amplified warming under drought conditions both in observations and future projectionsA drier condition or a higher emission scenario resulted in a larger range of mean temperature changes under future droughtsWe attributed the reduced mean temperatures under droughts to increasing winter droughts and higher atmospheric moisture conditions [ABSTRACT FROM AUTHOR]

The Clausius‐Clapeyron relationship holds that the atmospheric water vapor content enhances with warming temperatures, suggesting intensifications of precipitable water and also altering runoff generation. Drought conditions are determined by variations in water fluxes such as precipitation and runoff, which tightly connect with temperature scaling characteristics. However, whether and how water fluxes' scaling with temperatures may affect the evolution of droughts under climate change has not yet been systematically investigated. This study develops a cascade modeling chain consisting of the climate model ensemble, bias correction technique, and hydrological models to investigate the precipitation and runoff scaling relationships with warming temperatures under the current (1961–2005) and future periods (2011–2055 and 2056–2100), as well as their implications on future drought changes across 151 catchments in China. The results show that (1) precipitation (runoff) scaling relationships with temperatures are stable during different time periods; (2) return level analysis indicates drought risks are projected to become (1–10 times) more severe across central and southern catchments, where the precipitation (runoff) strengthens with rising temperatures up to a peak point and then decline in a hotter environment. The northeastern and western catchments, where a monotonic increasing scaling type dominated, are accompanied by drought mitigations for two future periods; (3) future changes in hydrological droughts relative to the baseline are (1–5 times) larger than those in meteorological droughts. These results imply that changes in future drought risks are highly dependent on the present precipitation (runoff)‐temperature relationships, suggesting a meaningful implication of scaling types for future drought prediction. Plain Language Summary: Drought hazards are determined by variations in water fluxes such as precipitation and runoff. Global climate warming has altered these terrestrial hydrological processes and subsequently changed drought conditions. Characterizing the responses of precipitation and runoff to warming climates and investigating their implications on future drought changes are important for drought early warning and prediction. Here we show that monthly precipitation and runoff either exhibit a monotonic increasing or the peak‐like structure (in which precipitation and runoff increase with warming temperatures up to a peak point and decline thereafter) with temperatures. The increasing relationship typically suggests future drought mitigation, while the hook structure type, which prevails in central and southern catchments in China, implies increasing drought risks. Our findings facilitate a better understanding of drought changes under climate change and provide a scientific basis for drought adaptation to climate change. Key Points: Monthly precipitation and runoff typically exhibit a monotonic increasing or hook structure with temperature scaling in ChinaThe hook structures typically imply future intensifying drought hazards, whereas the increasing scaling types infer drought mitigationsFuture changes in hydrological droughts relative to the historical baseline are larger than those in meteorological droughts [ABSTRACT FROM AUTHOR]

Drought is one of the most widespread and destructive hazards over the Loess Plateau (LP) of China. Due to climate change, extremely high temperature accompanied with drought (expressed as hot drought) may lead to intensive losses of both properties and human deaths in future. A hot drought probabilistic recognition system is developed to investigate how potential future climate changes will impact the simultaneous occurrence of drought and hot extremes (hot days exceeding certain values) on the LP. Two regional climate models, coupled with multiple bias‐correction techniques and multivariate probabilistic inference, are innovative integrated into the hot drought probabilistic recognition system to reveal the concurrence risk of droughts and hot extremes under different Representative Concentration Pathway (RCP) scenarios. The hot‐day index, TX90p, indicating the number of days with daily maximum temperature (Tmax) exceeding the 90th percentile threshold, and the Standardized Precipitation Index are applied to identify the joint risks on the LP using copula‐based methods. The results show that precipitation will increase throughout most of the LP under both RCP4.5 and RCP8.5 scenarios of 2036–2095, while Tmax may increase significantly all over the LP (1.8–2.7 °C for RCP4.5 and 2.7–3.6 °C for RCP8.5). The joint return periods of Standardized Precipitation Index and TX90p show that fewer stations will experience severe drought with long‐term hot extremes in two future scenarios. However, some stations may experience hot droughts that are more frequent and extreme, particularly certain stations in the southwest and south‐central regions of the LP with recurrence period less than 10 years. Key Points: A modeling system is developed to investigate future characteristics of simultaneous occurrence of drought and hot extremesPrecipitation projections from PRICIS and RegCM models were jointly corrected by the multidimensional copula modelResults show that some stations in partial area of Loess Plateau may experience hot droughts that are more frequent and extreme in future [ABSTRACT FROM AUTHOR]