Urbanization accelerates lake warming: evidence from China

The rapid rise in lake surface water temperature (LSWT) over the past few decades has become a global concern. Research on the spatial heterogeneity of lake warming and its mechanistic drivers is a key challenge. Studies have shown that urbanization induced impermeable surface expansion can lead to the warming of inland waters, however, large scale studies are limited, and the driving mechanisms remain unexplored. To address this knowledge gap, we analyzed the thermal characteristics of 587 major lakes across China and found significant regional differences in LSWT trends. Specifically, LSWT increased in highly urbanized and densely populated regions (0.19 ± 0.05 °C 10a -1) was 58.3% greater than in less urbanized regions (0.12 ± 0.03 °C 10a -1) (P < 0.05). Additionally, our findings indicate that the warming rate in urbanized lakes (0.16 ± 0.05 °C 10a -1) is 33.3% higher than in non-urbanized lakes (0.12 ± 0.03 °C 10a -1) (P < 0.05). Moreover, urbanized lakes with high urbanization intensity (UI) (0.21 ± 0.04 °C 10a -1) have warmed 31.3% faster than those with low UI (0.16 ± 0.05 °C 10a -1) (P < 0.05). An importance assessment suggested that urbanization modified the impact of air temperature (ΔAT = 32.0%), precipitation (ΔP = -14.9%), and evapotranspiration (ΔET = -13.4%) on LSWT warming. Under the combined influences of urbanization and future climate change, lake surface waters are expected to warm further. These findings offer valuable insights for assessing LSWT trends, particularly in regions experiencing both urban expansion and changing climate conditions.