Lake dynamics and its relationship to climate change on the Tibetan Plateau over the last four decades

Abstract

The high sensitivity of the Tibetan Plateau (TP) to global warming is ascribed not only to its high altitude and low temperature but also to the change in the components of water cycling, such as glaciers’ retreat, permafrost degradation, and lakes’ shrinkage or expansion. Among the components, change in lakes attracts more attention as lakes are crucial for local water management and are easier to monitor. But, how water cycling components respond to global change remains unclear, although they are crucial in understanding the regional environmental change. Lakes, glaciers, and permafrost data derived from meteorological records and remote sensing images were used to detect the change of the water environment on the TP from 1971 to 2013. The climate on TP changed toward a warm-humid condition in the last four decades. Three-quarters of the lakes were significantly expanded over the TP, and the summed area of all the lakes increased by 6061 km2 from 1975 to 2010. Panel regression showed that annual average air temperature (T), annual precipitation (P), and reference crop evapotranspiration (ET o ) regulate the change in lake surface area (LSA) on the entire TP. The change in LSA is more related to the change in P than in the other two factors, even in the catchment where lakes are recharged by water from glacier melting and permafrost degradation, especially in extremely arid and arid climate zones. Elevation and size affected the sensitivity of lakes to climate change with lakes in a high-elevation area more sensitive to T and small lakes more sensitive to T, P, and ET o . Warming-induced glacier’s retreat led to the significant lake expansion, while permafrost degradation might be responsible for the lake shrinkage in the seasonally frozen ground area due to the related cryogenic waterproof layer downward. Our results about the responses of lakes to climate change in different catchments were in accordance with the findings of previous studies about several typical lakes, which implied that overall response of all the lakes to climate change could be obtained by examining several typical lakes in the catchment level.