Climate change dominates historical runoff variations at multiple time scales in typical agricultural basin of South China

The Hanjiang River Basin (HRB) in South China The attribution identification of runoff variation is conducive to formulating climate change response strategies to cope with regional water resources problems. At present, the specific driving mechanisms of seasonal-scale runoff variation require further exploration and research. This study employs five runoff attribution methods, including linear regression, two hydrological models, and two elasticity methods, to quantitatively dissect the influences of climate change and human activities on runoff variation during 1960–2016 in the HRB. The abrupt change detection results indicate that 1972 is the abrupt change point of the runoff series in the HRB. The series is split into two periods: 1960–1972 (baseline period with limited anthropogenic influence) and 1973–2016 (change period). The average results from different methods unequivocally attribute the leading causes of runoff variation to climate change (43.92–135.01 mm), with human activities contributing less (−19.15–36.78 mm). Human activities are observed to partly offset the impact of climate change on runoff variation by approximately 1.3–28.4 %. Results from different methods show similar patterns, with smaller differences in the flood season than the non-flood season. The multi-method approach employed in this study provides valuable insights for policymakers and water resource planners seeking to address the complex interplay of climate change and human activities. • Extended climate elasticity method is adopted to seasonal runoff attribution. • Climate change is the main driving factor of seasonal and annual runoff variation. • Human activity partly offset the impact of climate change on runoff in flood season. • Results from five runoff attribution methods show similar patterns.