The Earth’s terrestrial carbon stocks have depleted an estimated 344 billion tons. Carbon losses amid water scarcity in climate-vulnerable drylands are a mounting challenge, and their restoration requires optimizing water-to-carbon biotransformation. Synthesizing thousands of worldwide experimental studies, we identify key biophysical pathways for enhancing carbon restoration and ecosystem resilience in global drylands, as follows: (i) Cropping diversification increases net primary productivity by 18.9% (n = 1296 studies); (ii) Regulated deficit irrigation cuts water use by 30–50% while improving yield-scaled water use efficiency by 3.4% (n = 9068 paired comparisons); (iii) Soil mulching increases land productivity by 22.2% (n = 48,144 paired comparisons); and (iv) Soil health rejuvenation strategies can sequester 1.2–3.8 t SOC ha⁻¹ yr⁻¹. Priorities to implement these biophysical pathways to enhance water-to-carbon biotransformation include: ‘smart’ irrigation, carbon dioxide fertilization-enhanced photosynthetic assimilation, rhizosphere engineering for microbiome-based nutrient solutions, biodegradable mulches replacing traditional polyethylene films, diversifying farming systems with low soil disturbance and climate-smart practices, and inclusive governance frameworks. These prioritized strategies reconcile water scarcity with carbon restoration to enhance dryland ecosystem resilience, which supports the UN’s Sustainable Development Goals.

Thermal conductivity and diffusivity for three pyroxenes, omphacite, jadeite, and diopside, were determined up to 14 GPa and 1000 K in the Kawai‐type multianvil apparatus via the pulse heating method. Measurements for omphacite are characterized by much lower thermal conductivity and thermal diffusivity than those of its two end‐members of jadeite and diopside, presumably because of the complex substitution of four cations (Na⁺¹, Ca⁺², Al⁺³, and Mg⁺²) in omphacite. Therefore, simple arithmetic averaging is unsuitable for estimating thermal conductivity and diffusivity of the jadeite‐diopside solid solution system. The thermal property of eclogite was estimated from those of garnet and omphacite. The thermal conductivity of eclogite is much smaller than that of harzburgite, which is assumed to compose of 80% olivine and 20% enstatite, implying that subducted oceanic crust impedes thermal conduction from the hotter wedge mantle to the subducting slab. Thermal structure simulation results show that temperature of the subduction zone is about 50°C decreased when the effect of oceanic crust is included.

Crystal preferred orientation (CPO) of antigorite is an important parameter for the interpretation of seismic anisotropies and related geodynamic processes in subduction zones. However, mechanisms for the development of various antigorite CPOs and their effects on seismic anisotropies in the forearc mantle still remain to be constrained. In this study, we investigated olivine and antigorite CPOs and calculated seismic anisotropies of the serpentinized peridotites from Val Malenco, Central Alps. The results show that antigorite in the olivine‐rich (weakly serpentinized) layer displays an L‐type CPO (i.e., (h0l) plane//foliation and [010] axis//lineation), whereas antigorite in the antigorite‐rich (highly serpentinized) layer develops an LS‐b‐type CPO (i.e., (001) plane//foliation and [010] axis//lineation). The antigorite L‐type CPO is most likely formed by diffusion and dislocation creep accommodated phase boundary sliding and substantial grain rotation at a higher temperature and smaller strain regime. In contrast, the development of an antigorite LS‐b‐type CPO requires diffusion and dislocation creep accommodated grain boundary sliding, smaller contribution of grain rotation, and significant role of dissolution‐precipitation creep at a lower temperature and larger strain regime. In this context, we propose an antigorite CPO distribution model in the forearc mantle. Based on this model and under vertically incident teleseismic waves, if significant serpentinization and asymmetric shearing do indeed occur within serpentinized layers, then strong and weak trench‐parallel seismic anisotropies can be expected for cold and warm moderate‐angle subduction zones, respectively. This model may provide an alternative interpretation on the seismic anisotropy observations in some modern subduction systems.

The hydrogen concentration and composition of garnets in the ultrahigh pressure eclogites at Shuanghe, eastern Dabieshan, were investigated using Fourier transform infrared spectroscopy and electron microprobe analysis. The OH absorption bands can be divided into four groups: (1) 3635–3655 cm^–1; (2) 3600–3630 cm^–1; (3) 3540–3580 cm^–1; and (4) 3400–3450 cm^–1 and the water content ranges from 45 to 2529 ppm. Based on the behaviour of the OH absorption band and the relationship between water content and the composition of garnets, the samples can be divided into two classes: samples with >400 ppm H2O and samples with ≤400 ppm H₂O. The water content of the former shows an obvious positive correlation with Ca atoms and a negative correlation with the Si, Mg and Fe²⁺ atoms per 12 anions, whereas the water content of the latter shows no obvious linear correlation with cations. It is concluded that the major mechanism of hydroxyl incorporation in garnets with >400 ppm H₂O is by the coupled substitution 4H +^Z□ → □+^ZSi in the tetrahedral site, and that several mechanisms are responsible for OH incorporation in garnets with ≤400 ppm H₂O.

Aqueous fluids are essential to extract slab‐trapped carbon at forearc to subarc depths and interpret the decarbonation efficiency of global subduction zones. A large amount of carbon survives beyond subarc depths. The behavior of such carbon, however, remains unclear owing to a lack of experimental studies. Here, we investigate the decarbonation behavior of carbonated oceanic crust containing different amounts of H₂O at pressures from subarc depths to the top of the mantle transition zone. We find that calcium‐rich carbonatitic liquids can form at temperatures of ∼950–1,150°C at depths below ∼150–300 km, corresponding to warm/cold thermal regimes in most subduction zones. Therefore, hydrous carbonatitic liquids should be pervasive in subduction zones, while extensive dehydration reactions and fluid activities are critical for creating carbonatitic liquids and preventing most of the surviving carbon from being subducted into the deep Earth.