Still severe drought in Europe: the JRC – CIMA – SLF report

A technical report on drought in Europe has recently been published. The document, which analyzes the situation up to the end of June and in various aspects (including vegetation stress and wildfire risk) was contributed by CIMA Research Foundation

Are we still in drought conditions? Did the rain in May and June mitigate it? And how is the rest of Europe doing? Just recently, the Joint Research Centre (JRC) published its latest technical report dedicated to drought, which also includes many researchers from CIMA Research Foundation among the authors.

The report analyzes the situation in June 2023, investigating different parameters and indices used in the assessment of drought and also reporting what we can expect for the rest of the summer season considering weather forecasts. Here we take up some of the main elements.

Precipitation

Italy has experienced a severe drought over the past year (we talked about it on our website). The phenomenon has not vanished - nor has it remained geographically confined. As highlighted by the JRC report, in fact, drought is still very present in most of Europe. If in the southern areas, however, it is likely going towards a recovery phase (most of Italian peninsula, for example, is not currently considered in a state of drought), in northern Europe it can be considered at the beginning. The Combined Drought Indicator, based on a combination of variables such as precipitation, soil moisture and vegetation health, shows that for much of Europe, in fact, the situation is still comparable to that of last year.

The lack of precipitation is the main cause of concern. For a year, in fact, there has been a negative anomaly in precipitation across the continent. Then, this spring, at least for some regions (including Italy, the Iberian Peninsula and the Balkans), precipitation even exceeded seasonal averages. It was not the same for other regions: the so-called "meteorological drought", understood precisely as a period in which precipitation is below the average for the period, affects various regions of the Baltic Sea, Scandinavia, Great Britain, Ireland and Germany, and begins to raise fears for the state of health on crops.

Moreover, seasonal forecasts suggest that precipitation in central and northern Europe will remain significantly low - in contrast to what is estimated to happen instead for the countries bordering the Mediterranean, for which forecasts indicate amounts above the seasonal average.

Snow

CIMA Research Foundation's main contribution to the current report is also part of the precipitation context. We recall, in fact, that precipitation does not only concern rain but also snow. Our Hydrology and Hydraulics Department has monitored the state of the Italian snow water resources throughout the winter, and the data collected were used in the JRC report to highlight how in Italy, despite a situation that can be defined as better than last year, the amount of water contained in the snow (Snow Water Equivalent, SWE), which is a form of water reserve, remained significantly scarce, especially in the Alps.

Colleagues from the Institute for Snow and Avalanche Research and Swiss Federal Institute for Forest, Snow and Landscape Research report a similar situation for the Swiss Alps. Since mid-December, in fact, high temperatures and low precipitation - also main characters of the Italian winter - have determined the lowest SWE ever recorded since 1998. However, the situation has improved more than in Italy, because the heavy precipitation that occurred from mid-March until May allowed the season to end with a SWE closer to the historical average, at least across the western part of Swiss Confederation.

Temperatures

Along with precipitation, temperatures are the second important element that influences drought. In fact, higher temperatures favor the evaporation of water from the soil.

As for temperatures, the report notes that they remained above average, for much of Europe, from January to May. For some regions (Iberian Peninsula, southern France, Eastern Europe and also for northern Italy), the temperature anomaly also reached +1.6°C.

Together, high temperatures and scarcity of precipitation have meant that soil moisture has been significantly reduced in central and northern Europe - a potentially critical condition for crops.

Vegetation and fire risk

In fact, the JRC report also reports the health status of vegetation, a parameter widely used in drought assessment and analyzed through an indicator called fPAR, derived from satellite data. By mid-June, vegetation stress was observable for almost the entire Iberian Peninsula, for most Mediterranean countries (with the exception of some Turkish and Italian regions), northern Austria, Belarus, Ukraine and Romania.

High temperatures and dry vegetation are also factors that influence the risk of wildfires, which in fact is estimated to be "from high to extreme" for the Iberian Peninsula and most of the Mediterranean regions - that the risk is a reality we can see, unfortunately, from the fires in Greece (here we told about our contribution to ERCC right at the beginning of the fires) and in Italy.

Overall, these data indicate the need for careful and continuous monitoring, because everything seems to indicate a high risk to the water supply. The impacts are already visible on crops in the Iberian Peninsula, which has had to maintain limited irrigation, and worries about water stress that could affect crops in the Baltic regions, Britain, Ireland, Germany and the Benelux region.

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