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Information about past floods and historical precipitation records is fundamental to the management of water resources, but observational records usually cover only the last 100–150 years. Using several different data sources, such as newly digitized meteorological data from several stations in the southeastern part of Romania, from historical newspapers of that time, and daily reanalysis of large-scale data, here we provide a detailed analysis of the atmospheric circulation conditions associated with a devastating flood event which took place in June 1897. The floods in June 1897 were one of the most devastating natural disasters in Romania's history, and they were caused by heavy rainfall that started at the beginning of May and continued for several weeks, resulting in widespread flooding, especially in the eastern part of the country. The most affected areas were the cities of Braila and Galati, located on the main course of the Danube River, where the floods caused extensive damage to infrastructure, including homes, bridges, and roads, and disrupted transportation and communication networks. The heavy rainfall events occurring in June 1897 and the associated flood peak were triggered by intrusions of high potential vorticity (PV) anomalies toward the southeastern part of Europe, persistent and pivotal cutoff lows over the analyzed region, and increased water vapor transport over the southeastern part of Romania. We argue that digitizing and analyzing old meteorological records enables researchers to better understand Earth's climate system and make more accurate predictions about future climate change. [ABSTRACT FROM AUTHOR]

In the context of forecasted climate change scenarios, the growth of forest tree species at their distribution margin is crucial to adapt current forest management strategies. Analyses of beech ( Fagus sylvatica L.) growth have shown high plasticity, but easternmost beech populations have been rarely studied. To describe the response of the marginal beech population to the climate in the far east sites of its distribution, we first compiled new tree ring width chronologies. Then we analyzed climate-growth relationships for three marginal beech populations in the Republic of Moldova. We observed a relatively high growth rate in the marginal populations compared to core distribution sites. Our analyses further revealed a distinct and significant response of beech growth to all climatic variables, assessing for the first time the relationship between growth and vapor pressure deficit (VPD) which described how plant growth responds to drought. These results highlight that accumulated water deficit is an essential limiting factor of beech growth in this region. In conclusion, beech growth in the easternmost marginal population is drought-limited, and the sensitivity to VPD will need to be considered in future studies to update the forest management of other economic and ecologically important species.

Risk management has reduced vulnerability to floods and droughts globally 1,2 , yet their impacts are still increasing 3 . An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data 4,5 . On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change 3 ., (© 2022. The Author(s).)

The region situated between the mountain area and the lowlands in NE Romania (East-Central Europe) is experiencing increased competition for water resources triggered by a growing population, intensification of agriculture, and industrial development. To better understand hydrological cycling processes in the region, a study was conducted using stable isotopes of water and atmospheric trajectory data to characterize regional precipitation and vapour sources derived from the Atlantic Ocean, Mediterranean and Black Seas, as well as recycled continental moisture, and to assess and partition these contributions to recharge of surface and groundwater. Atmospheric moisture in the lowlands is found to be predominantly delivered along easterly trajectories, while mountainous areas appear to be dominated by North Atlantic Ocean sources, with moisture transported along mid-latitude, westerly storm tracks. Large-scale circulation patterns affect moisture delivery, the North Atlantic Oscillation being particularly influential in winter and the East Atlantic pattern in summer. Winter precipitation is the main contributor to river discharge and aquifer recharge. As winter precipitation amounts are projected to decrease over the next decades, and water abstraction is expected to steadily increase, a general reduction in water availability is projected for the region.