Land-atmosphere feedback amplifies circulation-dominant fire weather risk over eastern Siberia

Wildfires in eastern Siberia have intensified significantly in recent decades. This intensification is closely linked to rising vapor pressure deficit (VPD), a key indicator of fire weather risk. Previous studies have shown that atmospheric circulation increases VPD through subsidence-induced warming and drying, but the extent to which the circulation-driven VPD increase is realized through land–atmosphere feedback remains unclear. Here we show that atmospheric circulation explains about 60% of the 2004–2024 summer VPD trend over eastern Siberia, while circulation-triggered land-atmosphere feedback provides a major amplification pathway, accounting for about 42% of the circulation contribution. Mechanistically, reduced Laptev sea ice concentration favors a regional anomalous anticyclonic circulation over eastern Siberia, suppressing precipitation and depleting soil moisture. The resulting soil drying shifts surface energy from latent toward sensible heat, further amplifying regional VPD. These findings reveal a key land-surface pathway through which circulation intensifies fire weather risk and provide a broader framework for understanding similar changes in other fire-prone regions. Atmospheric circulation dominates the increase in fire weather risk over eastern Siberia in the past two decades, with circulation-triggered land-atmosphere feedbacks amplifying about 42% of that effect, as suggested by attribution of vapor pressure deficit based on reanalysis data.