# Impact of Climate Change on the Major Eco-Hydrological Parameters in the Dongting Lake Basin
## 1 Introduction  
As is widely accepted, the global climate is experiencing a significant change in terms of warming patterns [1, 2]. Global warming has emerged as a key environmental concern around the world. According to the Sixth Assessment Report of the International Intergovernmental Panel on Climate Change (IPCC), global greenhouse gas emissions increased by an average of 1.3% per year between 2010 and 2019. If such trend continues, the average annual temperature increase will reach 3.2 \({}^{\circ}\)C by the end of the 21 st century, thereby resulting in considerable social and climate-related risks [3]. The warming of theplanet is predicted to accelerate the water cycle, leading to an increase in extreme weather events such as droughts and floods [4]. In the field of meteorology and natural disasters, studies on the temporal trends and spatial distribution of extreme climate events, and related research on the various influencing factors of extreme climate events have become a trending topic for governments and scholars [5]. In recent years, the significant changes observed in the global climate have prompted widespread concern. The climate of the Dongting Lake Basin has also been impacted by such changes. As a result, there is a growing concern regarding climate change within the region. Climate change, land use and cover change, and human disturbance can lead to a range of ecological effects that affect ecological health [6; 7]. Further, climate change has a significant impact on the quality of ecosystems [8]. Evapotranspiration (ET) is a core component that links energy balance and water balance, and represents water consumption [9]. Gross primary productivity (GPP) of vegetation represents total carbon emissions, which is the source of food and wood production [10]. The long-term trend of GPP can effectively detect the environmental changes in the watershed ecosystem and reflect the quality of the ecosystem environment. GPP can be used as an important indicator of the regional ecosystem carbon sinks or sources. ET is the main pathway for energy and water transfer and conversion in the three systems of terrestrial plants and atmospheres, and one of the important components of the hydrosphere, atmospheric, and bioregional water cycle. ET has an important role in the energy needs and material transformations of the earth's atmosphere and hydrosphere biosphere. GPP and ET provide an important component of terrestrial eco-hydrological processes, and they are closely coupled through leaf stomatal-regulated transpiration and photosynthesis. GPP and ET can be taken as significant parameters of regional eco-hydrology to reflect regional eco-hydrological changes. GPP and ET are significant components of the hydrological processes in terrestrial ecosystems and have a strong impact on the ecological environment. They are regulated by leaf stomata and coupled through transpiration and photosynthesis. In essence, ET and GPP have similar response characteristics under climate change scenarios [11]. Research on the control mechanisms of ET and GPP can offer a scientific foundation for evaluating vegetation productivity and water consumption, as well as attributing them to specific causes. The Dongting Lake Basin serves important ecological functions, such as flood control, climate regulation, water purification, and maintenance of biodiversity. Since Dongting Lake has a powerful water storage function, the tremendous water storage capacity of this ecosystem has a great role in regulating river runoff, intercepting surface runoff, and controlling floods. The large amount of evapotranspiration in the Dongting Lake Basin could increase the humidity of the air and it could be manifested in lowering the air temperature, hence attenuating the strong atmospheric changes. The unique water dynamics and environmental conditions of Dongting Lake have reproduced extremely rich biodiversity and harbor extremely valuable species genes.