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New European Drought Benchmark – Boosted by that?


The drought event from 2018 to 2020 was the most severe drought in more than 250 years.

A peer-reviewed publication

HELMHOLTZ ENVIRONMENTAL RESEARCH CENTER – UFZ

Major drought events in Europe in the last 250 years
PICTURE DESCRIPTION: (A) DEFINITION AND TIME THROUGH EUROPE IN THE PERIOD OF 1766 TO 2020 BASED ON THE MODEL. BULLET SIZE CONTRIBUTE TO TOTAL EXTENSION EXPAND. (B) TEMPORARY ASSESSMENT OF THE TEMPORARY LEVEL. EXHIBITION EXHIBITION 2018–2020 BRINGS THE BIGGEST EXPAND OF ALL OTHER EVENTS OF ALL TIME. (C – E) SPACE MAP DISTRIBUTIONS OF TIME DIFFERENTLY BETWEEN MONTHLY IN THREE MAJOR EVENTS. INVESTMENTS IN THE DISPLAY MAP IS COVERED ON THE COURSE OF THE REACTIVE RECOVERY PHASE. see more
CREDIT: UFZ

Pastures wither, stream beds dry up, forests die and power plant output declines – the drought years 2018, 2019 and 2020 were exceptional and had a significant impact on nature and the economy. Previously, it was not clear where they should be classified in terms of their history. We now know: “The drought of 2018 to 2020 sets a new standard for drought in Europe,” said Dr. Oldrich Rakovec, UFZ moderator and lead author of the journal paper. The Future of the Earth Journal of the American Geophysical Union. The scientists documented this using a large set of data and modeling techniques that allowed them to reconstruct historic droughts from 1766 and compare their extent to the 2018 drought. until 2020.

As a result, drought from 2018 to 2020 affected about a third of Europe’s land area, especially in central Europe, such as Germany, France and the Czech Republic. “No other drought event in the last 250 years has had such a large spatial scale,” explains Oldrich Rakovec. The total duration of the drought event in Europe was also unusually long, starting in April 2018 and lasting until December 2020: 33 months. Only the drought from 1857 to 1860 lasted a little longer out of a total of 35 months. Furthermore: The drought from 2018 to 2020 will also continue into 2021 and 2022 in deeper areas (i.e. 2m deeper than the ground). “Although 2021 will be wetter and provide much needed water in the upper soil layer, important for sustaining agricultural activities, moisture does not penetrate to greater depths,” said the UFZ operator. .

The mean dry time was also unusually long in the 50 x 50 km grid cells that the scientists subdivided Europe for their modeling activity. Because a drought event evolves dynamically in space and time (i.e. it begins at one point, then continues to grow, and finally ends somewhere else) its average duration is different. with its total time. In this case, the 2018-2020 event shows an average drought duration of 12 months.

In the past, only drought events from 1857 to 1860 lasted longer, with an average duration of 13 months. Scientists define a drought as a time when the current soil-water content in the 2m-high soil layer falls below 20% over the course of 250 years. To reconstruct these historic droughts, the scientists used the mHM hydrological model developed at the UFZ. Among other things, this environmental model can be used to estimate soil moisture based on past temperature and precipitation records.

Rising air temperatures also hit a historic record during the 2018-2020 drought, with an anomaly of 2.8 degrees Celsius above the long-term average over the past 250 years. “Previous droughts were colder than recent droughts, in which average temperatures remained largely unchanged,” said Dr Rohini Kumar, UFZ moderator and co-author of the paper. The effects of a drought event are significantly more severe if, in addition to the precipitation deficit (about 20% for major drought events in previous centuries), warmer conditions prevail. . This synergistic effect leads to more evaporative losses, leading to a decrease in the water-soil level. The scientists also looked at the consequences of a lack of water for agriculture during this drought. They compared average annual crop yields for wheat, cereal corn and barley, between 2018 and 2020 with yields between 1961 and 2021. The results indicated that harvests were significantly reduced in countries mainly affected by the 2018-2020 drought. For example, cereal corn production declined by 20 to 40 percent in the Benelux countries, Germany and France; wheat fell by up to 17.5% in Germany; and barley by 10% in nearly all of Europe.

How droughts will develop in Europe in the future also depends on the severity of global warming. Scientists modeled latent and duration of drought for two representative concentration pathways (RCPs), describing whether future greenhouse gas emission scenarios would be more moderate (RCP4. 5) or will continue unhindered (RCP8.5) until Year 2100. The scientists determined that the average duration of drought increased significantly by up to 100 months for the RCP4.5 scenario, during as drought levels are forecast to increase, covering up to 50% of Europe. The situation is different from the extreme RCP8.5 scenario: In this case, the average duration of the drought could last more than 200 months and the extent of the drought could affect 70% of Europe. “Decision makers should prepare for significantly more severe drought events in the future. Especially for the formulation of new agricultural policies, this should be seen as a wake-up call to assess appropriate measures to reduce the risk of water shortages”, said Dr. Luis Samaniego, co-author of the study. article and Team Leader Stochastic and Soil Surface said. Hydrology Working Group at KFZ. On a regional basis, this could be the establishment of large reservoirs, such as underground storage systems; smart and intelligent irrigation technology or hybridization of better heat tolerant crop varieties.


JOURNEYS

AGU Advances

DOI

10.1029 / 2021EF002394

RESEARCH METHODS

Simulation / computational modeling

RESEARCH SUBJECTS

Do not apply

ARTICLE TITLE

The 2018–2020 multi-year drought sets a new benchmark in Europe.

ARTICLE PUBLICATION DATE

March 15, 2022

From EurekAlert!



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