2026

1. [Calvo-Sancho et al. 2026] Abstract = This study provides a comprehensive evaluation of the hydroclimatic transition of the Iberian Peninsula (1950–2024), characterizing its spatial structure and temporal evolution. By integrating ERA5 atmospheric water balances, high-density station observations, and stepwise regression models, we show evidence that the region is undergoing a structural redistribution of precipitation. The atmospheric water balance indicates a transition toward a moisture-limited sink, characterized by declining surface evaporation and rising atmospheric evaporative demand, while net moisture convergence and total precipitation remain statistically unchanged. Station-level analysis robustly validates this volumetric stability (present in 90.5% of the territory) but reveals an underlying zero-sum redistribution: the fractional contribution of extreme precipitation (Rp95) has systematically increased relative to ordinary rainfall (Ro) across 29.6% of the observational network, intensifying along the coasts while ordinary rainfall declines inland (redistribution precipitation-climate scenario). To determine the drivers of this shift, stepwise regressions were applied using the annually aggregated daily frequencies of large-scale circulation patterns (NAO, WeMO, subtropical ridges, and blocks). Results confirm that the stationary frequency of these dynamic drivers successfully explains the long-term stability of total precipitation volume but does not account for the intensification of extremes. The models reveal distinct seasonal mechanisms: while winter extremes exhibit an amplification of dynamic efficiency, autumn extremes (Rp95) remain entirely uncoupled from large-scale circulation. Furthermore, the intensification of these autumn extremes has accelerated significantly in the recent period (1988–2024). Since the dynamic triggers remain stable, these results provide diagnostic evidence highly consistent with thermodynamic amplification. Operating within a moisture-enriched environment, driven by long-term increases in total column water vapor (TCWV), classical synoptic configurations now act as more efficient triggers, thereby enhancing coastal extremes and shifting the Peninsula toward a more extreme, hydrologically volatile regime.
   Tendencias de precipitación y amplificación termodinámica

2. [Calvo-Sancho et al. 2026] Abstract: Global warming alters the hydrological cycle, increasing heavy rainfall events worldwide. In October 2024, Valencia (Spain) experienced rainfall accumulations in a few hours surpassing annual averages (771.8 mm in 16 h in the official weather station at Turís) and breaking the record for one hour rainfall accumulation in Spain (184.6 mm), resulting in 230 fatalities. Here, we present a physical-based attribution study employing a km-scale pseudo-global warming storyline approach to assess the contribution of anthropogenic climate change. We show that present-day conditions led to a 20% °C⁻¹ increase in 1-hour rainfall intensity, exceeding Clausius-Clapeyron scaling. This intensification was driven by enhanced atmospheric moisture from warmer sea surface temperatures, leading to increased convective available potential energy, stronger updrafts, and microphysical changes including elevated graupel concentrations. These results demonstrate that anthropogenic climate change could intensify the occurrence of flash-floods in the Western Mediterranean region: in this particular case, it intensified the 6-h rainfall rate by 21%, amplified the area with total rainfall above 180 mm by 55%, and increased the volume of total rain within the Jucar River catchment by 19% compared to the pre-industrial era. This study highlights the urgent need for effective adaptation strategies and improved urban planning to reduce the growing risks of hydrometeorological extremes in a rapidly warming world.
   Attribution of DANA, Valencia

3. [Chandra et al. 2026] Abstract: “AI psychosis” or “delusional spiraling” is an emerging phe- nomenon where AI chatbot users find themselves dangerously confident in outlandish beliefs after extended chatbot conver- sations. This phenomenon is typically attributed to AI chat- bots’ well-documented bias towards validating users’ claims, a property often called “sycophancy.” In this paper, we probe the causal link between AI sycophancy and AI-induced psy- chosis through modeling and simulation. We propose a simple Bayesian model of a user conversing with a chatbot, and for- malize notions of sycophancy and delusional spiraling in that model. We then show that in this model, even an idealized Bayes-rational user is vulnerable to delusional spiraling, and that sycophancy plays a causal role. Furthermore, this effect persists in the face of two candidate mitigations: preventing chatbots from hallucinating false claims, and informing users of the possibility of model sycophancy. We conclude by dis- cussing the implications of these results for model developers and policymakers concerned with mitigating the problem of delusional spiraling.
   psicopathy in chatbots

4. [Silvio et al. 2026] abstract = ABSTRACT This review paper examines the development and application of climate predictions, primarily at seasonal timescales, as actionable information for decision-making, with a specific focus on the Mediterranean region. It illustrates and analyses the steps required to transform climate model probabilistic forecasts into user-defined information, emphasising the iterative nature of climate service development. By leveraging tools such as bias adjustment, downscaling, probabilistic calibration and impact models, these services provide tailored solutions to key sectors including energy, water supply, transport and agriculture. The paper discusses the contributions of global initiatives, such as the Global Framework for Climate Services (GFCS), and EU-funded projects like EUPORIAS, MEDSCOPE and MED-GOLD, which have advanced sector-specific applications of climate predictions in the region. These initiatives illustrate how tailored climate services can address critical challenges ranging from renewable energy planning to drought risk mitigation and agricultural yield forecasting. The review highlights persistent challenges, including limited forecasting skill in the Mediterranean area, data accessibility issues and the need for robust impact-based verification. To enhance the uptake and effectiveness of climate services, the review recommends fostering interdisciplinary collaboration, promoting iterative co-production with users, improving the communication of uncertainty and forecast skill, and ensuring the sustainability of services beyond project lifetimes. This work underscores the potential of climate services to enhance resilience in the Mediterranean region, bridging the gap between scientific advances and practical applications.
   Seasonal prediction and services Mediterranean

5. [Gualdi et al. 2026] abstract = The capability to predict climate fluctuations from sub–seasonal–to–decadal timescales would yield large and significant socio–economic benefits. On the other hand, our limited understanding of the mechanisms and processes responsible for predictability and systematic model errors hampers our ability to simulate and forecast climate variability. As a result, current forecast quality remains relatively unsatisfactory, particularly in the mid-latitudes and in the Mediterranean basin. In recent years, several research studies and collaborative projects have been conducted in order to improve the skill of forecasting systems and the quality of the data and climatic information they produce. This effort has led to substantial advancements in understanding Mediterranean climate variability and its drivers, as well as to improvements in the capability to provide reliable climate predictions for this region. The main objective of this paper is to review and discuss the current understanding of climate variability and sources of predictability in the Mediterranean basin and surrounding areas, to assess the current capability of climate prediction systems in order to provide skilful predictions in this region to feed services in relevant socio-economic sectors. Examples of advanced tools and innovative methodologies recently developed to enhance predictions, both in terms of forecast skill and of the quality of the data they provide (e.g., sub–sampling and bias correction), will also be discussed.
   Seasonal prediction and sources Mediterranean

   [Heys et al. 2026] abstract = For decades, economists have known that using gross domestic product (GDP) alone to guide policy is problematic. The metric is mainly a measure of market production, albeit one with strong marketing and branding, and misses key elements of what makes a good life. Nevertheless, failure to agree on alternatives has held back the debate over what should replace it
   GDP

6. [Ren et al. 2026] Abstract: Climate change is intensifying the occurrence of hydric events, such as summer water availability and winter freeze-thaw cycles, which are increasingly significant in temperate regions. These events pose substantial threats to tree hydraulic functions and thereby limiting tree growth. In this study, we investigated the compound effects of climate-induced stressors and neighborhood crowding on tree growth, and tested how species functional traits mediate these responses. We combined annual growth data over 8 years from 593 individuals representing 20 tree species in Northeast China to evaluate the relative influence of water availability, freeze-thaw cycles, and their interaction with local crowding on tree growth, and how species functional traits mediate these responses. Our findings indicate that tree growth declined with increasing freeze-thaw cycles frequency, whereas summer water availability had no detectable effect. Tree growth was limited by neighborhood crowding, which appeared to operate largely independently of freeze-thaw cycles. In addition, species with higher xylem hydraulic efficiency, lower wood density and lower specific leaf area grew faster and were more sensitive to freeze-thaw cycles, while species with higher xylem hydraulic efficiency were less sensitive to neighborhood crowding. Our results demonstrate distinct and independent roles of freeze-thaw cycles and neighborhood crowding in shaping temperate tree growth, suggesting that considering the freeze-thaw cycles may improve predictions of temperate forest dynamics facing altered climate changes. Furthermore, species traits can capture how temperate trees cope with different stressors, highlighting the importance of integrating functional traits for a more comprehensive understanding of tree responses to environmental stressors.
   TRW and freezing/thawing

7. [Royé et al. 2026] Abstract: As cities heat up, climate shelters are increasingly vital for protecting people from extreme heat. Beyond temporary emergency stopgaps, Spain’s pioneering experience shows how climate, health and governance align to turn these spaces into enduring infrastructures of care and resilience.
   TRW and freezing/thawing