Divergent Spatiotemporal Patterns and Climate Responses of Lateral and Internal Lake Drainage in the Northern Permafrost Region

Abstract Lake drainage is a key manifestation of permafrost degradation with implications for hydrology, landscape dynamics and carbon feedbacks. Lake drainage occurs through two distinct mechanisms, namely lateral drainage and internal drainage. Here, we identified 3,969 lake drainage events from 2001 to 2020 across the northern permafrost region using high‐resolution, multi‐temporal satellite imagery. For each drainage event, we determined its specific timing and mechanism, enabling the first circumpolar classification of lake drainage types at monthly resolution. Lateral drainage accounted for 90.6% of all cases and peaked in June, aligning with increased snowmelt and precipitation in continuous permafrost regions. In contrast, internal drainage events were concentrated in March, when soils begin to thaw in sporadic and isolated permafrost zones with limited surface water input. These findings highlight distinct seasonal and climatic drivers of lake drainage and underscore the need to differentiate between surface and subsurface pathways when assessing permafrost landscape responses.