Beer in danger

Could extreme weather also threaten the production of a popular drink?

Climatic events can have different effects on the overall yield and bitterness of hops. We can encounter combinations of phenomena in which only one variable is extreme, but also phenomena in which two extreme variables occur simultaneously (e.g. drought and heatwave). High temperatures and the development of heat waves are also facilitated by drought. Over the last 20 years, a feedback loop has developed between soil temperature and surface air temperature - warmer soil warms the atmosphere, and a warmer atmosphere causes the soil to warm, thereby maintaining the rise in atmospheric temperature. The increasing frequency of heat waves and droughts in hop-growing regions is leading to increasing income instability in beer production, affecting major hop growers across Europe.

A recent study by several of our scientists looked at the vulnerability of hop production due to combined climatic and meteorological events in Europe, focusing, for example, on identifying the effect of the duration of heat waves and droughts on yield reduction. This is the first work of its kind. The study covers key hop-growing regions across the European Union, such as Hallertau (Germany); Ústecko, Žatecko and Tršicko (Czech Republic); Kent (UK); Alsace (France); Lublin (Poland); Koroška (Slovenia) and León and Galicia (Spain).

Based on the models, the researchers determined the likely distribution of daily rainfall and maximum temperatures, which are used to assess the risk of simultaneous drought and heat waves during the hop season. The researchers then estimated the risks of lower yields from hop heads in the target areas. The results show that longer and more severe droughts and heatwaves occur more frequently than similar shorter periods. The highest level of risk was then estimated in the large hop-growing areas of the Czech Republic and Germany. A total of 22.4 %, 12.5 % and 7.2 % of EU areas for commercial hop production fell into the categories for moderate, high and very high risk of yield loss respectively. Analysis of the total damage between April and August further indicated that more than 62.7 % of yield losses were caused by high temperatures during the drought and 21.5 % of losses were caused by dry and cool conditions in the regions. In addition, the warmer European droughts caused a 29-68 % drop in yield of quality aromatic hops. This indicates that hop yields are very sensitive to these climatic events, mainly due to the slower adaptation of hops compared to field crops.

POTOPOVÁ, Vera, Ondřej LHOTKA, Martin MOŽNÝ and Marie MUSIOLKOVÁ. Vulnerability of hop-yields due to compound drought and heat events over European key-hop regions. International Journal of Climatology [online]. [cited 2020-11-19]. ISSN 0899-8418. Available from: doi:10.1002/joc.6836

Not good news for beer drinkers! https://www.rmets.org/node/417841