Continuous increase in evaporative demand shortened the growing season of European ecosystems in the last decade

Despite previous reports on European growing seasons lengthening due to global warming, evidence shows that this trend has been reversing in the past decade due to increased transpiration needs. To asses this, we used an innovative method along with space-based observations to determine the timing of greening and dormancy and then to determine existing trends of them and causes. Early greening still occurs, albeit at slower rates than before. However, a recent (2011–2020) shift in the timing of dormancy has caused the season length to decrease back to 1980s levels. This shortening of season length is attributed primarily to higher atmospheric water demand in summer that suppresses transpiration even for soil moisture levels as of previous years. Transpiration suppression implies that vegetation is unable to meet the high transpiration needs. Our results have implications for future management of European ecosystems (e.g., net carbon balance and water and energy exchange with atmosphere) in a warmer world.

Mehdi Rahmati, Alexander Graf, Christian Poppe Terán, Wulf Amelung, Wouter Dorigo, Harrie-Jan Hendricks Franssen, Carsten Montzka, Dani Or, Matthias Sprenger, Jan Vanderborght, Niko E. C. Verhoest, Harry Vereecken