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Water availability in the dry western United States (US) under climate change and increasing water use demand has become a serious concern. Previous studies have projected future runoff changes across the western US but ignored the impacts of ecosystem response to elevated CO2 concentration. Here, we aim to understand the impacts of elevated CO2 on future runoff changes through ecosystem responses to both rising CO2 and associated warming using the Noah‐MP model with representations of vegetation dynamics and plant hydraulics. We first validated Noah‐MP against observed runoff, leaf area index (LAI), and terrestrial water storage anomaly from 1980 to 2015. We then projected future runoff with Noah‐MP under downscaled climates from three climate models under Representative Concentration Pathway 8.5. The projected runoff declines variably from the Pacific Northwest by −11% to the Lower Colorado River basin by −92% from 2016 to 2099. To discern the exact causes, we conducted an attribution analysis of the modeled evapotranspiration from two additional sensitivity experiments: one with constant CO2 and another one with static monthly LAI climatology. Results show that surface “greening” (due to the CO2 fertilization effect) and the stomatal closure effect are the second largest contributors to future runoff change, following the warming effect. These two counteracting CO2 effects are roughly compensatory, leaving the warming effect to remain the dominant contributor to the projected runoff declines at large river basin scales. This study suggests that both surface “greening” and stomatal closure effects are important factors and should be considered together in water resource projections.

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Stem cells possess regenerative powers and multidirectional differentiation potential and play an important role in disease treatment and basic medical research. Urine-derived stem cells (USCs) represent a newly discovered type of stem cell with biological characteristics similar to those of mesenchymal stromal cells (MSCs), including their doubling time and immunophenotype. USCs are noninvasive and can be readily obtained from voided urine and steadily cultured. Based on advances in this field, USCs and their secretions have increasingly emerged as ideal sources. USCs may play regulatory roles in the cellular immune system, oxidative stress, revascularization, apoptosis and autophagy. This review summarizes the applications of USCs in tissue regeneration and various disease treatments. Furthermore, by analysing their limitations, we anticipate the development of more feasible therapeutic strategies to promote USC-based individualized treatment.

The interannual variability (IAV) of gross primary productivity (GPP) reflects the sensitivity of GPP to climate variations and contributes substantially to the variations and long‐term trend of the atmospheric CO2 growth rate. Analyses of three observation‐based GPP products indicate that their IAVs are consistently correlated to terrestrial water storage anomaly over the central US, where episodic droughts occur. A land surface model explicitly representing plant hydraulics and groundwater capillary rise with an adequate soil hydraulics well captures the observed GPP IAV. Our sensitivity experiments indicate that, without representations of plant hydraulics and groundwater capillary rise or using an alternative soil hydraulics, the land model substantially overestimates the GPP IAV and the GPP sensitivity to water in the central US. This study strongly suggests the use of the van Genuchten water retention model to replace the most commonly used Brooks–Corey model, which generally produces too strong matric suction of soil water especially in dry conditions, in land surface modeling. This study highlights the importance of plant and soil hydraulics and surface–groundwater interactions to Earth system modeling for projections of future climates that may experience more intense and frequent droughts.

Carbon sink trading is an important aspect of carbon trading in China, and can have important significance in offsetting carbon emissions and improving ecological compensation. The use of unmanned aerial vehicles (UAVs) offers new opportunities for shrub carbon sink and accounts as a substitute for time-consuming and expensive plot investigations to estimate the carbon sink by using the aboveground carbon stock monitored by UAV. However, the UAV-based estimation of the aboveground carbon stock of densely planted shrubs still faces certain challenges. The specific objectives of this research are as follows: (1) to test the statistical relationship between the aboveground carbon stock and volume of a densely planted shrub belt, and (2) to develop a model to estimate aboveground carbon stock by monitoring the volume of the densely planted shrub belt using a UAV. The study showed that (i) the aboveground carbon stock would increase with the increase in the volume of the shrub belt, (ii) an estimation model of the aboveground carbon stock of the densely planted shrub belt was developed ( R 2 = 0.89 ,   P < 0.01 ), and (iii) the validation assessment to estimate aboveground carbon stock by using the UAV-based estimation model produced a coefficient of determination of R2 = 0.74 and an overall root mean square error of 18.79 kg CO2e. Good prediction ability of the model was determined using leave-one-out cross-validation (LOOCV). This output information is valuable for the design of operations in the framework of precise carbon-sink accounting of shrubs. In addition, a method using an UAV was developed and validated for the quick estimation of aboveground carbon stock for densely planted shrubs, thereby providing a potential alternative to time-consuming and expensive plot investigations of aboveground carbon-stock accounting, which is necessary for shrub projects in the carbon trading market in China.

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