Jet stream controls on European climate and agriculture since 1300 CE

Area of Science:

• Paleoclimatology
• Climate Dynamics
• European Climate History

Background:

• The jet stream significantly influences Northern Hemisphere climate variability.
• Summer jet stream position in the North Atlantic-European sector (EU JSL) affects regional climate patterns, but its long-term variability and impacts are poorly understood.
• Understanding pre-industrial EU JSL variability is crucial for assessing future climate risks.

Purpose of the Study:

• To reconstruct interannual summer EU JSL variability from 1300 to 2004 CE.
• To investigate the impacts of EU JSL variability on past climate extremes and societal events.
• To provide insights into long-term climate dynamics and their societal consequences.

Main Methods:

• Utilized three temperature-sensitive European tree-ring records to reconstruct summer EU JSL variability.
• Compared the reconstructed EU JSL data with independent historical records (grape harvest, grain prices, plagues, mortality).
• Analyzed biophysical, economic, and demographic impacts associated with past EU JSL variations.

Main Results:

• Developed a robust reconstruction of summer EU JSL variability from 1300-2004 CE (R² = 38.5%).
• Identified contrasting summer climate extremes linked to EU JSL variability since 1300 CE.
• Documented significant biophysical, economic, and demographic impacts, including wildfires and epidemics, correlating with EU JSL shifts.

Conclusions:

• Long-term EU JSL variability has driven significant climate extremes and societal impacts in Europe for centuries.
• Historical climate-societal linkages associated with the jet stream provide a basis for understanding future risks.
• Considering EU JSL variability is essential for evaluating amplified future climate risks, especially with projected changes in jet stream behavior.