Europe experienced an exceptional drought in 2022, resulting in widespread agricultural losses (Baruth et al., 2022; Toreti et al., 2022; Faranda et al., 2023), reductions in hydropower and wind energy, increased solar potential (Toreti et al., 2022; Copernicus Climate Change Service, 2022a), disruptions to river transport and ecosystems, severe water shortages, forest fires, and substantial anomalies in carbon emissions (Toreti et al., 2022; Faranda et al., 2023; Copernicus Climate Change Service, 2022b; Gharun et al., 2024).

Previous analyses have investigated the event's drivers and its links to anthropogenic climate change, showing that it produced the largest terrestrial water storage deficit since 2002 across Central–Southern Europe, with human-induced warming amplifying drought intensity by more than 30 % (Bevacqua et al., 2024). The drought was primarily driven by a persistent anticyclonic anomaly, which, together with other large-scale atmospheric circulation features – a blocking over Western Europe and a displaced jet stream – extreme heat, and elevated atmospheric evaporative demand, exacerbated its severity (Faranda et al., 2023; Garrido-Pérez et al., 2024). Easterly and southerly dry winds associated with the strengthened anticyclone further reinforced these conditions (Herrera-Lormendez et al., 2023). However, although this drought is extraordinary in the context of the current climate, soil droughts on a similar scale are projected to occur twice as often in West-Central Europe in a +2 °C warming (Schumacher et al., 2024).

While previous studies have elucidated the large-scale circulation and climate change influence, the specific role of anomalous moisture and temperature sources in shaping the drought's evolution remains unclear. Here, we addressed this gap by quantifying the anomalous sources of atmospheric moisture uptake and temperature during the 2022 European drought, providing new insights into the coupled thermodynamic and dynamic processes governing the origin and development of extreme droughts in Europe.

The 2022 drought affected extensive areas across both the Atlantic and Mediterranean climatic regions of Europe (Fig. S1, fourth column). To analyse the event, we defined the drought-affected area using the 6-month Standardized Precipitation Evapotranspiration Index (SPEI6) for June–August 2022 (≤-1.28), capturing the core summer phase of maximum compound heat-drought impacts (“Supplementary Methods”). This area was then divided into two subregions based on their dominant oceanic moisture sources – the North Atlantic ocean (NATL) and the Mediterranean Sea (MED) (Fig. 1a) as indicated in Gimeno-Sotelo et al. (2024): the NATL-influenced region, covering northern and western Europe (hereafter NW_Europe), and the MED-influenced region, encompassing southern and eastern Europe (SE_Europe).

Monthly anomalies for key meteorological variables related to drought occurrence (Fig. 1b–h) illustrate the temporal evolution across both European subregions. Persistent deficits in precipitation (Fig. 1b) and soil moisture (Fig. 1e), together with strong increases in atmospheric evaporative demand (Fig. 1d) and thermal excess (Fig. 1h), concentrated primarily during May–August 2022, representing the active hydro-climatic peak period of the drought. While cumulative multi-scalar indices like SPEI6 (Fig. 1c) display their lowest values later in autumn due to the 6-month memory effect of preceding deficits, the active atmospheric drivers (precipitation suppression, high atmospheric demand, and thermal stress; Garrido-Pérez et al., 2024) clearly peaked during the May–August window. Suppression of vertical motion and persistence of high-pressure systems sustained these drought conditions. Vertical velocity anomalies at 500 hPa (Fig. 1f) indicate reduced upward motions except for September (the drought-breaking month) and November 2022. Persistent anticyclonic conditions and blocking activity (Faranda et al., 2023; Garrido-Pérez et al., 2024) are further evidenced by positive geopotential height anomalies at 850 hPa (Fig. 1g). This stable circulation favoured strong and widespread surface warming across both regions (Fig. 1h), more pronounced over NW_Europe during summer (∼ 2.2 K), reflecting thermal persistence. These results highlight spatio-temporal differences between the subregions, driven by coupled land–atmosphere processes, evidenced by coherent anomalies in precipitation, soil moisture, evapotranspiration, temperature, and atmospheric stability (Figs. S1–S3).

At a large scale, and complementary to land–atmosphere interactions, the moisture flux patterns (measured as vertically integrated water vapour transport (IVT) anomalies, Fig. S4) also reveal circulation patterns modulating the event. While the subtropical Atlantic exhibited positive IVT anomalies, western Europe experienced moisture deficits before drought peak. The reduced inflow from the Mediterranean Sea limited replenishment of atmospheric moisture and intensified the drought (with partial recovery from September), acting as a drought-intensifying factor (Gimeno-Sotelo et al., 2024).

The role of changes in atmospheric moisture transport from source regions modulating droughts is recognized as a key factor in understanding their behaviour and intensity (Gimeno et al., 2012; Liu et al., 2020). To quantify this effect during the 2022 European drought, we applied a Lagrangian approach using the FLEXPART model (Pisso et al., 2019) and ERA5 reanalysis data (Hersbach et al., 2020) (“Supplementary Methods”).

First, to evaluate moisture uptake (MU) feeding the study regions, backward trajectories were tracked to identify regions with evaporation minus precipitation greater than zero. MU anomalies were then averaged over five predefined non-overlapping domains (Fig. S5a): the two European subregions affected by the drought (NE_Europe and NW_Europe; Fig. 1a), the Mediterranean Sea (MED), the broader North Atlantic ocean sector, and the remaining continental North Atlantic land area (excluding the evaluated European subregion). Quantifying MU was crucial for assessing the contributions from each source and capturing the key components of the moisture transport dynamics shaping drought conditions.

Second, to quantify the precipitation contribution (PC), forward simulations were conducted to track moisture loss (evaporation minus precipitation < 0) originating from Europe's primary moisture sources – the NATL and the MED (Fig. S5b, Gimeno et al., 2012; Gimeno-Sotelo et al., 2024) – as well as from the two drought-affected European subregions themselves (Fig. 1a).

Marked temporal and spatial contrasts emerged between NW_Europe and SE_Europe in the evolution of MU and PC anomalies (Fig. 2a–h). From January to April, moisture availability preceding the peak drought was slightly enhanced, as both subregions exhibited positive MU anomalies mainly from local sources (Fig. 2a–d). In contrast, notable deficits in PC occurred from MED and NATL sources, particularly from the latter, while PC values from the subregions themselves remained close to climatology (Fig. 2e–h). On average, anomalies during this period were markedly negative, ranging from -0.4 to -0.8 mm d⁻¹ for both dominant oceanic sources (Fig. 2h).

From May to August (the hydro-climatic peak of drought), MU intensified from multiple sources, with a slight decrease from the Mediterranean during some months. This coincides with predominantly negative PC anomalies, particularly from NATL – although less pronounced than in preceding months (Figs. S6–S8). During this period, mean moisture support anomalies from MED and NATL were about -0.2 mm d⁻¹ (Fig. 2h). These patterns are coherent with reduced moisture flux and persistently stable atmospheric conditions associated with a sustained blocking pattern (Figs. 1f, g, S3) over the North Atlantic and Europe (Faranda et al., 2023; Garrido-Pérez et al., 2024).

During September to November, land-based sources became dominant for SE_Europe, while oceanic sources prevailed for NW_Europe (Fig. 2a–d). Positive PC anomalies, mainly from the two European subregions and the Mediterranean, indicate partial hydrological recovery, most evident in SE_Europe (Fig. 2h). In contrast, negative PC anomalies from the NATL were marked but weaker than those before the drought peak. Overall, MU increased, despite some declines south of 30° N (Fig. S6), reflecting the atmosphere's greater capacity to retain moisture under higher temperatures (Soden and Held, 2006; Allen and Ingram, 2002) (Fig. 1h). However, PC behaviour associated with the MED and NATL oceanic sources and the two European subregions suggests that, although moisture availability increased, atmospheric instability required for convection and precipitation was largely absent until September, consistent with stable conditions driven by persistent high-pressure systems (Faranda et al., 2023; Garrido-Pérez et al., 2024), which inhibited upward motion and convection and diverted moisture fluxes away from the preferred sources (positive omega500 and Z850 anomalies, and reduced IVT; Figs. 1f, g, S4).

In general, weakening oceanic contributions to precipitation were key to sustaining the 2022 drought, which began to disappear by the late-season reactivation of regional moisture inputs (Figs. S7, S8). This behaviour reflects the decoupling identified in our analysis: despite enhanced regional moisture uptake, precipitation contributions from the NATL and MED sources remained strongly suppressed due to persistent anticyclonic circulation and divergent moisture transport patterns. Specifically, in September, drought across southern Europe ended abruptly as intense rainfall was triggered by a deep North Atlantic trough extending into central Europe and a strong subtropical high over North Africa (Figs. 2e, f; S3). This pattern advected warm, moist Mediterranean air toward southeastern Europe (Fig. S8), initiating severe convection under unstable conditions (Fig. 1f, g; Z850 and omega500 negative anomalies). This shift marked the end of the prolonged dry period.

The 2022 European drought was additionally characterized by a considerable near-surface temperature excess (Fig. 1h), accompanying several heatwaves (Schumacher et al., 2024). This thermal anomaly, linked to persistent stable atmospheric conditions (Faranda et al., 2023; Garrido-Pérez et al., 2024), was a key factor in exacerbating drought severity (Bevacqua et al., 2024). Using the Lagrangian framework (Papritz and Röthlisberger, 2023) (“Supplementary Methods”), temperature anomaly sources for the two drought-affected European regions were decomposed into adiabatic, diabatic, and advective components (Fig. 3), allowing identification of physical drivers arising from vertical motion, horizontal transport, and heat exchange.

Only months exhibiting positive near-surface temperature anomalies over the drought-affected regions were included in the Lagrangian temperature-source decomposition. To assess the spatial origin of these processes, the contributing physical drivers were evaluated over the predefined North Atlantic land and ocean sectors, as well as the Mediterranean Sea, maintaining non-overlapping boundaries with the evaluated European subregions (Fig. S5a).

The two European subregions exhibit a dipolar pattern of total temperature anomaly sources, with positive anomalies over North Africa, the Mediterranean region, the North Atlantic Ocean, and central-eastern Europe, and negative anomalies north of 50° N. This pattern was strongest at the drought peak and expanded spatially during January–February and May (Figs. S9, S10). Averaged series for both subregions reveal a shared physical baseline dominated by adiabatic warming, with subtle quantitative variations across periods and domains (Fig. 3).

Over both subregions (Fig. 3a–b), the adiabatic term dominates year-round, with pronounced positive values during the main drought period (May–August), indicating persistent warming driven by subsidence and adiabatic compression. The advective term generally exhibits negative anomalies during these same months, due to air flux from cooler higher latitudes, which partially offset the adiabatic warming. The diabatic term also remains negative. Over the North Atlantic land and oceanic source regions (Fig. 3c–f), anomalies are generally weaker than over the two European subregions, with modest positive adiabatic and slightly negative diabatic and advective components, indicating minor remote contributions to surface warming for the two European subregions. In contrast, over the Mediterranean Sea, strong positive adiabatic anomalies occur (Fig. 3g–h), particularly during May–August and autumn, reflecting intense subsidence. These periods correspond to the strongest total temperature anomalies, particularly in SE_Europe.

A percentage-based perspective (Fig. S11) indicates that temperature anomalies for both European regions are largely controlled by the continental regions themselves, explaining ∼ 60 %–85 % of the total signal, while the Mediterranean Sea accounts for only ∼ 10 %–30 %. For the adiabatic term, European subregions contribute ∼ 40 %–60 %, with Mediterranean influence near ∼ 10 %–20 %. A similar pattern is seen in the advective term, especially over NW_Europe, where the European subregions explain between 40 %–60 % of the anomalies. The diabatic term is comparatively stronger over the Mediterranean (∼ 20 %–40 %), although the continental effects from the European subregions still dominate (∼ 50 %–70 %).

The dominant adiabatic term is the fingerprint of a persistent anticyclonic circulation pattern (Faranda et al., 2023; Garrido-Pérez et al., 2024), which results in descending air (Figs. S9, S10), confirming the major role of adiabatic processes in controlling European temperature anomalies driven by summer anticyclones and mid-tropospheric subsidence (Röthlisberger and Papritz, 2023; Hamal and Pfahl, 2025). The negative advective term over the two European subregions reflects anticyclonic circulation moving air from cooler northeastern Europe into the warmer European subregions (Figs. S9, S10).

The global cooling observed over the two subregions, linked to the diabatic term, is the result of the compensation of three processes with different net effects on the temperature: (i) the warming by enhanced evaporation (which occurs mainly over the ocean) resulting in enhanced condensation in the air with latent heat absorption during the liquid to vapour phase transition and the cooling for inhibited evaporative (Röthlisberger and Papritz, 2023) over central European land areas, due to reduced soil moisture (Bevacqua et al., 2024) (Figs. S12, S13), resulting in diminished condensation in the air (ii) the warming by upward transfer of sensible heat from the surface to the atmosphere, (Fig. S14), and (iii) the cooling by the imbalance in surface net longwave radiation, under predominantly clear-sky and stable atmospheric conditions – particularly during the summer drought peak – as indicated by positive anomalies in outgoing longwave radiation (Figs. S12, S14); being the cooling processes dominant over the warming ones.

Our results show that a driving force behind the 2022 European mega-drought was not a lack of atmospheric moisture, but persistent atmospheric stability that prevented moisture from becoming rainfall. A long-lasting anticyclonic pattern suppressed precipitation, diverted humid Atlantic and Mediterranean inflows, and triggered widespread adiabatic warming that locked the region into deep dryness.

By integrating Lagrangian moisture-uptake and precipitation contribution diagnostics with a temperature source decomposition, our analysis provides new quantitative evidence of a marked decoupling between moisture availability and precipitation formation. Despite enhanced regional moisture uptake, precipitation contributions from the Atlantic and Mediterranean sources remained strongly negative throughout most of the year. This decoupling, driven by the combined action of persistent anticyclonic circulation and large-scale subsidence, had not been previously quantified for the 2022 event.

Furthermore, applying a novel source-based regionalization (North-Western vs. South-Eastern Europe, tied to Atlantic and Mediterranean sources, respectively) reveals contrasting regional trajectories in moisture uptake and precipitation deficits. Tracking these dynamics across the three stages of the event (pre-onset, peak, and recovery) demonstrates how this decoupling evolved over time: it was sustained during the peak by descending air, adiabatic warming, and muted oceanic precipitation contributions to precipitation, until an abrupt synoptic shift toward unstable synoptic conditions reactivated regional moisture sources and broke the drought. Its abrupt termination highlighted the system's sensitivity: a shift toward unstable synoptic conditions was enough to reactivate regional moisture sources and break the drought.

These findings demonstrate that, in a warming climate, the severity of future European droughts will depend not only on atmospheric moisture availability but on the large-scale dynamics conditions controlling when and where rainfall can occur.