Ideas and perspectives: Mineralizing fluid control on foreign elements in biogenic CaCO3: insights from otoliths Biogeosciences DOI 10.5194/bg-23-2831-2026 24 April 2026 Fish otolith formation is key for understanding the incorporation of elements into biominerals. It is often assumed that the final step of biomineralization consists of inorganic precipitation as the fluid where biominerals form can hardly be sampled. Thanks to fish ear anatomy, this can be overcome with otoliths. By comparing otolith formation and inorganic precipitation, we proved that this assumption is not always true. Our findings could refine models and shed light on biomineralization. Read more
Technical note: High Nash–Sutcliffe Efficiencies conceal poor simulations of interannual variance in seasonal regimes Hydrology and Earth System Sciences DOI 10.5194/hess-30-2337-2026 23 April 2026 Common metrics used to evaluate hydrologic models make it relatively easy to achieve high performance scores in highly seasonal catchments. However, we analysed 18 hydrologic models and found that almost all were worse at simulating interannual variability and change in seasonal streamflow regimes. This suggests that climate change impacts on streamflow may not be accurately predicted in highly seasonal tropical, alpine, and polar regions, which are highly vulnerable to climate change. Read more
Multi-hazard risk assessment and management: pathways for the Sendai Framework and beyond Geoscience Communication DOI 10.5194/gc-9-185-2026 22 April 2026 Natural hazards like floods, earthquakes, and landslides are often interconnected which may create bigger problems than when they occur alone. We studied expert discussions from an international conference to understand how scientists and policymakers can better prepare for these multi-hazards and use new technologies to protect its communities while contributing to dialogues about future international agreements beyond the Sendai Framework and supporting global sustainability goals. Read more
Evaluation of stratospheric transport in three generations of Chemistry-Climate Models Atmospheric Chemistry and Physics DOI 10.5194/acp-26-5249-2026 21 April 2026 Accurate representation of stratospheric transport in Chemistry-Climate Models is essential for reliable climate projections. This study evaluates three generations of models using observational data and reanalyses, identifying persistent biases and their potential causes. Some biases persist or even worsen in newer models. These findings highlight key limitations and inform efforts to improve models and advance understanding through process-based studies and enhanced observations. Read more
Interplay of North Atlantic freshening and deep convection during the last deglaciation constrained by Iberian speleothems Climate of the Past DOI 10.5194/cp-22-797-2026 20 April 2026 Stable isotope data of a precisely dated stalagmite from northwestern Iberia indicate gradual North Atlantic meltwater input during the last glacial maximum, followed by abrupt surges early in the last deglaciation. The first abrupt surge was decoupled from first cooling about 810 years later – unlike later events – which reveals that the Atlantic circulation’s sensitivity to meltwater is variable and related to the evolving background climate boundary conditions. Read more
Growth and decay of the Iceland Ice Sheet through the last glacial cycle Climate of the Past DOI 10.5194/cp-22-825-2026 17 April 2026 We simulated the Icelandic Ice Sheet over the last 120 kyr using an ice sheet model constrained by geological data with robust uncertainty assessment. At the Last Glacial Maximum, ice reached the continental shelf break, with a potential ice bridge connecting to the Greenland Ice Sheet. Model consistency with geological constraints during deglaciation is only possible with meltwater-driven ice fracture at the ice sheet margin, destabilizing the marine ice sheet and accelerating its collapse. Read more
Proglacial wetlands: an overlooked CO2 sink within recently deglaciated landscapes SOIL DOI 10.5194/soil-12-441-2026 17 April 2026 When glaciers retreat, new land surface is revealed. Using detailed glacial retreat maps, it is possible to determine for how long a location has been ice-free. That age is used in this study to analyse how fast carbon is incorporated into the soil. Our results show that the wetness of the soil strongly determines the CO2 uptake and carbon incorporation rates. Wetlands cover a small percentage of the land surface but are nonetheless important for the carbon storage in the deglaciated area. Read more
Drivers and implications of declining fossil fuel CO2 concentrations in Chinese cities revealed by radiocarbon measurements Atmospheric Chemistry and Physics DOI 10.5194/acp-26-5085-2026 16 April 2026 Our study indicates fossil fuel CO2 (CO2ff) reductions in Chinese megacities via atmospheric Δ(14CO2) and δ(13CO2) measurements, driven by coal-to-gas transitions and combustion efficiency improvement. The 24-year record show steeper declined urban RCO/CO2ff ratios than inventory estimates, implying underestimation of efficiency improvements and CO reductions. Integrating top-down observations with inventories is critical to track policy-driven emission shifts and optimize co-benefit strategies. Read more
Widespread occurrence of large molecular methylsiloxanes in ambient aerosols Atmospheric Chemistry and Physics DOI 10.5194/acp-26-5005-2026 16 April 2026 We identify a previously unrecognized class of synthetic organic compounds, large molecular methylsiloxanes, in ambient aerosols across diverse environments in three countries. These compounds are present at substantial levels, primarily originating from traffic emissions related to engine lubrication. Their high abundance and significant daily human exposure suggest potential, yet still poorly understood, implications for both health and climate. Read more
Geological factors and fracture distribution in deep and ultra-deep sandstones in Kuqa Depression, Tarim Basin, China Solid Earth DOI 10.5194/se-17-643-2026 15 April 2026 This study integrates geological and geophysical data to examine controls of sedimentary factors, earth stress, and tectonic structure on fracture distribution in deep and ultra-deep sandstones in Kuqa Depression. Key findings show fracture density increases with sandbody thickness and paleostress magnitude, is higher near faults and fold hinges, and is favored by thinner sand-mud interbeds. Increased horizontal stress differences contributes to reduced fracture apertures. Read more