Investigation of lake shrinkage attributed to climate change over the past 33 years in Inner Mongolia, China

Inner Mongolia, located in northern China and bordered by Mongolia and Russia, has numerous lakes. Constrained by water scarcity, precious lakes play key roles in degraded grassland ecosystems and the social and economic development of Inner Mongolia. This study combines 1815 Landsat image interpretations and ground-based surveys to track the area changes in 573 lakes in Inner Mongolia during the period 1987–2019. Our results demonstrate that the number of dried-up lakes increased by 0.87 per year, the number of lakes with water areas below 0.1 km2 increased by 1.02 per year, and the number of lakes with water areas between 0.1 and 1 km2 increased by 0.39 per year. The number of lakes with areas larger than 1 km2 shows a decreased or fluctuating trend. The lake area in Inner Mongolia increased at a rate of 7.04 km2/year from 1987 to 1998 but then shows an overall decreasing trend at a rate of 0.71 km2/year over the next 20 years. The period from 1999 to 2010 was the most serious period of lake shrinkage in Inner Mongolia in the past 30 years, with a shrinkage rate of 33.99 km2/year. The climate changes from wet to dry and from dry to wet are the main reasons for the breakpoint occurrence of the lake area time series in the 2000s and 2010s, respectively. The response of lake area changes to climate-related factors has significant regional differences. In addition, intensification of human activities, such as the rapid development of livestock and coal mining, is also the main driver of lake change. The multiple regression model shows that the contribution of climate-related variables and human activity–related variables to the change in lake area over the 1987–2019 time period was about 40% and 60%, respectively.