The Mediterranean Sea is one of the first regions where sea surface temperature (SST) increase was linked to greenhouse effects and global warming. Due to its sensitivity to climate variability and its high impact on local and remote climate conditions, much effort has been made to assess the SST variability in the Mediterranean as a whole. However, the Mediterranean is composed of several basins, each of which plays a different role in its conveyor belt’s function. This study focuses on the basin of the Tyrrhenian Sea which represents one of the crucial areas for deep mixing of the Mediterranean main water masses. Thirty-seven years (1982–2018) of satellite-derived data were used to investigate the SST variability in relation to large-scale and local forcing mechanisms. A significant warming trend of 0.034 ± 0.004 °C/year was found, which led to an average warming of 1.288 ± 0.129 °C over the considered period. The observed warming presents time-dependent spatial patterns as well as changes in the seasonal cycle. Our results highlight that the Tyrrhenian’s individual long-term surface variability has different characteristics than the Mediterranean as a whole and provide insight into the relative influence of large-scale teleconnection patterns and local air-sea interaction on this variability.

Climate change is exerting complex and transformative effects in the Arctic and Antarctic; regions that are essential to global climate, biodiversity, and sustainable futures. Given the polar regions’ roles in Earth’s system, a robust, coordinated, and innovative strategy to monitor and manage climate change effects is needed. Insufficient baseline data, inconsistent international collaboration, and short-term financing are obstacles to effectively monitor these changes. This hinders our understanding of biodiversity shifts, their implications for food security, and climate change mitigation. Confronting the impacts of climate change will require interdisciplinary collaboration and genuine participation of nations, including Indigenous communities. This sentiment includes facilitating international cooperation to address scientific objectives despite political tensions. Additional recommendations include establishing regular international requirements to track progress based on available science, optimizing the use of existing infrastructure and resources, enhancing data sharing practices, and securing long-term financing to sustain research. While the existing pan-Antarctic and pan-Arctic initiatives present useful strategies, these initiatives are not a silver bullet. They do, however, provide a starting point for further work. Ultimately, by building upon existing initiatives and harnessing their successful components, we can address limitations of short-term or fragmented studies. We outline tools and data resources for polar research, examples of existing collaborative efforts to build upon, and Indigenous knowledge systems that provide valuable resources for this undertaking.

In this study, 17 hydrologists with different experience in hydrological modelling applied the same conceptual catchment model (HBV) to a Greek catchment, using identical data and model code. Calibration was performed manually. Subsequently, the modellers were asked for their experience, their calibration strategy, and whether they enjoyed the exercise. The exercise revealed that there is considerable modellers’ uncertainty even among the experienced modellers. It seemed to be equally important whether the modellers followed a good calibration strategy, and whether they enjoyed modelling. The exercise confirmed previous studies about the benefit of model ensembles: Different combinations of the simulation results (median, mean) outperformed the individual model simulations, while filtering the simulations even improved the quality of the model ensembles. Modellers’ experience, decisions, and attitude, therefore, have an impact on the hydrological model application and should be considered as part of hydrological modelling uncertainty.

The Ross Ice Shelf floats above the southern sector of the Ross Sea and creates a cavity where critical ocean-ice interactions take place. Crucial processes occurring in this cavity include the formation of Ice Shelf Water, the coldest ocean water, and the intrusion of Antarctic Surface Water, the main driver of frontal and basal melting. During the winter, a polynya forms along the Ross Ice Shelf edge, producing a precursor to Antarctic Bottom Water known as High Salinity Shelf Water. Due to the difficulty of direct exploration of the Ross Ice Shelf in the winter, processes occurring there have been only hypothesized to date. Here we show thermohaline observations collected along the Ross Ice Shelf front from 2020 to 2023 using unconventionally programmed Argo floats. These measurements provide year-round observations of water column changes in and around the Ross Ice Shelf cavity, allowing to quantify production of High Salinity Shelf Water, ocean heat content and basal melt rates.