*4.2. Implications*

Our results predicted the future hydrological regime under RCP8.5 scenario, and it may bring some consequences. The increasing ET will likely lead to drier conditions in the TNR, especially in those arid regions (i.e., the IRB), where the SM may decrease. This finding imply that climate change may cause dryland expansion and exacerbate the risk of land degradation and desertification. Moreover, R would also rise in future, particularly in areas with dense population (i.e., the HRB), which may enhance the risk of flooding. Besides, the fluctuation in R may lead to the amplification of the inter-annual gap in water resources, so more solutions may need to be done to balance the temporal distribution.

Land cover change due to urbanization may slowly inhibit the increase of ET to some degree, but accelerate R in most areas. These effects are much stronger in the eastern basins than in the western ones. The majority of arid and semi-arid areas are located in the IRB, where effects are limited, while in the humid areas, such as the SRB, LRB, and HRB, increasing R caused by LCC may increase the risk of floods in the summer, especially in those places where the cities are densely structured. Considering that climate change may also have the similar effects, floods in these areas would be severe problems. Additionally, in arid and semi-arid regions, such as IRB, the ecological restoration programs have expanded the areas of forest or grass, and such change may increase the ET and decrease the R and SM, which can further intensify desertification and other forms of environmental degradation, since the rising temperature may have exacerbated these risks.

Overall, the progress of ecological programs may be unable to help balance neither spatial nor temporal distribution. In humid areas, the risk of floods may be heightened, especially in summer, while in arid and semi-arid areas, the desertification and drought could not be solved. Such results could aggravate the results "dry ge<sup>t</sup> drier, wet ge<sup>t</sup> wetter", which are caused by climate change [39–41].
