Multi-model assessment of groundwater recharge across Europe under
warming climate
Abstract
Climate change threatens the sustainable use of groundwater resources
worldwide by affecting future recharge rates. However, assessments of
global warming’s impact on groundwater recharge at local scales are
lacking. This study provides a continental-scale assessment of
groundwater recharge changes in Europe, past, present, and future, at a
(5 x 5) km2 resolution under different global warming levels (1.5 K, 2.0
K, and 3.0 K). Utilizing multi-model ensemble simulations from four
hydrologic and land-surface models (HMs), our analysis incorporates
E-OBS observational forcing data (1970-2015) and five bias-corrected and
downscale climate model (GCMs) datasets covering the near-past to future
climate conditions (1970-2100). Results reveal a north-south
polarization in projected groundwater recharge change: declines over
25-50% in the Mediterranean and increases over 25% in North
Scandinavia at high warming levels (2.0-3.0 K). Central Europe shows
minimal changes (±5%) with larger uncertainty at lower warming levels.
The southeastern Balkan and Mediterranean region exhibited high
sensitivity to warming, with changes nearly doubling between 1.5 K and
3.0 K. We identify greater uncertainty from differences among GCMs,
though significant uncertainties due to HMs exist in regions like the
Mediterranean, Nordic, and Balkan areas. The findings highlight the
importance of using multi-model ensembles to assess future groundwater
recharge changes in Europe and emphasize the need to mitigate impacts in
higher warming scenarios.