Climate-induced decline in the quality and quantity of European hops calls for immediate adaptation measures

Acknowledgements: This work was supported by the project SustES—Adaptation strategies for sustainable ecosystem services and food security under adverse environmental conditions (CZ.02.1.01/0.0/0.0/16_019/0000797) to M.T., the Technology Agency of the Czech Republic (No. SS02030040, SS02030018) to M.M.Funder: Ministry of Education, Youth and Sports of the Czech Republic - project SustES - Adaptation strategies for sustainable ecosystem services and food security under adverse environmental conditions Technology Agency of the Czech Republic - No. SS02030040, SS02030018.A recent rise in the global brewery sector has increased the demand for high-quality, late summer hops. The effects of ongoing and predicted climate change on the yield and aroma of hops, however, remain largely unknown. Here, we combine meteorological measurements and model projections to assess the climate sensitivity of the yield, alpha content and cone development of European hops between 1970 and 2050 CE, when temperature increases by 1.4 °C and precipitation decreases by 24 mm. Accounting for almost 90% of all hop-growing regions, our results from Germany, the Czech Republic and Slovenia show that hop ripening started approximately 20 days earlier, production declined by almost 0.2 t/ha/year, and the alpha content decreased by circa 0.6% when comparing data before and after 1994 CE. A predicted decline in hop yield and alpha content of 4–18% and 20–31% by 2050 CE, respectively, calls for immediate adaptation measures to stabilize an ever-growing global sector