The Aral Sea in Central Asia plays an essential role in the socio-economic development of the region. During the last six decades, there has been remarkable changes observed in the water level and areal extent of the Aral Sea Basin; however, the causes behind these changes are unclear. This study quantifies the impacts of climatic and anthropogenic drivers on Aral Sea and the contributions made by these drivers to the variations observed in the Aral Sea Basin. The spatial and temporal seasonal variations in groundwater budget have been analyzed using the total water storage (TWS) of the basin from 2002 to 2015. The results from this study revealed significant increases in the the mean air temperature, precipitation, and potential evapotranspiration rate from 1960 to 2015 in the Aral Sea Basin. The TWS time-series shows a statistically significant declining trend of about 2 to 4 cm per year presented by the surface water storage. Based on the average monthly values of TWS, March 2005 presented the highest anomaly ~7.85 cm, while October 2008 showed the lowest anomaly ~8.22 cm between 2002 to 2015. The groundwater level indicates a small increasing trend of approximately 0.05 cm/year during the study period. Furthermore, the negative relationship between water level, climatic, and anthropogenic factors showed that these factors projected critical impact on the water level fluctuations within the Aral Sea Basin.

The Aral Sea is an indispensable component of the socio-economic progress of Central Asia but has undergone substantial ecological transformations over the last few decades, primarily due to global warming and human activities. Among these changes, the basin area has decreased, and water levels have dropped. This paper focuses on a comprehensive analysis of the spatial variation of key climate parameters, such as temperature, precipitation, and potential evapotranspiration over the Aral Sea. Moreover, we examined the transformation of seasonal water areas in the Aral Sea during the growing and non-growing seasons between 2002 and 2017 and the influence of climate and human factors on these changes using Landsat satellite data. Our results indicate that the western section of the Aral Sea has experienced a reduction in water area by 2.41 km² and 1.83 km² during the warm (R² = 0.789) and cold (R² = 0.744) seasons, respectively, over the investigated period. The decrease in lake water volume during the warm season can be attributed to local climate variations, as a strong negative correlation exists between seasonal water storage change and temperature (potential evapotranspiration). The correlation analysis shows that the water change in the northern part of the Aral Sea during the growing season has a significant positive correlation with temperature (R = 0.52) and an insignificant negative correlation with precipitation (R = −0.22). On the contrary, in the west and east parts of the Aral Sea, there is a significant negative correlation with temperature (R = −0.71 and −0.62) and a high positive correlation with precipitation (R = 0.71 and 0.55) during the growing season.

Since 1960, water level began to decline considerably due to anthropogenic impact of the Aral Sea (AS), and it is continued to this day, which has led to dramatic changes in the climate around the AS, including ambient temperatures and sharp increases in evapotranspiration. Although, it isn't possible to see normal trend in this precipitation. Time series analysis of the FTI (First Time Interval 1901-1960) and STI (Second Time Interval, 1960-2015), highlighting climate change around the AS, based on Global Climate Data, suggests that there is a significant negative difference between precipitation and evapotranspiration during the drying of the AS. It is possible to see the logical compatibility of the air temperature and difference between precipitation and evapotranspiration observed around the AS, i.e. the temperature fluctuation trend is positive and contrary to the difference between precipitation and evapotranspiration negative trend, which means that the annual hydrological budget was reduced according to the time scale. In this article, determining the AS as the central point, we analyze the changes in the thermal and hydrological processes observed on the AS, as well as the impact to the environment of anomalous climate change observed on and around the sea like the drying out of the AS.

In the past several decades, substantial changes were observed in Central Asia’s land cover. Water-sensitive Central Asia has experienced an increase in farming and expansion of urban areas. These are considered the main reasons for water level reduction in the Aral Sea. The disappearance of the Aral Sea has not only affected the climate of the region but also caused regional land cover changes. In this article, we analyse the temporal variation of the Normalized Difference Vegetation Index (NDVI) and its correlation with climatic variables in the territory of the Aral Sea Basin from 1982 to 2015 using Global Inventory Modelling and Mapping Studies (GIMMS) and Moderate Resolution Imaging Spectroradiometer (MODIS). The results indicate that the mean annual NDVI value recorded a weak positive trend of 0.0023/10a over the last 34 years. The Hurst index is used to test whether the tendency observed in past can be extrapolated in the future or not. Our results showed, the Hurst exponent indicates that the vegetation dynamic trend was consistent, which means that NDVI values will continue to rise in the future. During the study period, precipitation and surface soil moisture increased in the growing season, which affected the temperature during the non-growing season.

The Gravity Recovery and Climate Experiment (GRACE) mission, operational from 2002 to 2017, provided critical measurements of Earth’s gravity field anomalies which have been extensively used to study groundwater and terrestrial water storage (TWS) dynamics. In this research, we utilize GRACE data to identify, model, and analyze potential climate parameters contributing to the reconstruction of TWS variability in the Aral Sea Basin region (ASB). We assess the impact of climate change and anthropogenic nature management on TWS change using a quantitative method. Our analysis reveals a significant decline in the TWS at a rate of 0.44 cm year⁻¹ during the 2005–2009 period, primarily attributed to the prevailing drought conditions in the region. Notably, the estimated impact of anthropogenic influence on TWS during the same period of −1.39 cm year⁻¹ is higher than the influence of climatic variables, indicating that anthropogenic activity was the dominant factor in water resource depletion. In contrast, we observed an increase in TWS at a rate of 0.82 cm year⁻¹ during the 2013–2017 period, which can be attributed to the implementation of more effective water resource management practices in the ASB.