Changes in winter climatic conditions and growing-season precipitation-temperature interactions affect cereal yields in Northern Europe

In Northern Europe, climate change lengthens the growing season and increases temperatures during this period, but it also raises exposure to adverse climatic events such as reduced timely precipitation, temperatures above the optimum, and frost damage. Nonetheless, the net effect of positive and negative changes of climatic conditions in Northern Europe is still unclear, and it remains underexplored whether future climatic conditions, particularly in winter, will be beneficial or detrimental for crop yields.

To assess future risks, we analyzed a regional Single Model Initial-Condition Large Ensemble (CRCM5-LE) over Northern Europe under the RCP8.5 scenario (1955–2099), focusing on agriculturally relevant climatic variables over winter. Projections showed increasing winter temperatures and precipitation, and a decrease in snow depth across most regions. Combined effects of these changes resulted in more frequent periods of snow depth <5 cm below 60°N, and an increased number of freeze-thaw cycles. Both of these conditions negatively affect autumn-sown crops during their winter dormant period, increasing susceptibility to frost damage. Trends toward these unfavorable winter conditions emerged as early as the first half of this century.

In parallel, by using statistical models we quantified past response of county-averaged spring- and autumn-sown cereal yields in Sweden (1965–2020) to a wide range of observed temperature- and precipitation-related indicators across physiologically relevant crop development stages. Average growing season climatic conditions explained 75–85% of yield variability and outperformed short-term extremes. Yield reductions were associated with low precipitation or prolonged dry spells combined with high temperatures, as well as excessive precipitation under cool conditions.

Together these results show that without targeted adaptation strategies, climate change is unlikely to benefit cereal yields in Northern Europe, as a result of changes in winter conditions, and reductions in growing season precipitation and increases in temperature.