## 3 Results  
### The Spatiotemporal Patterns of Land Use and Land Cover Change  
The land-use spatial pattern shows significant heterogeneity in 2010 (Table 1, Figure 3a). Grassland, with the largest proportion of 74.4%, occupied the west and northwest regions with less precipitation and poorer soil condition. Cropland, accounting for 17.5%, is mostly near the eastern and southern areas, around the basins of the Yellow River, Weihe River, Fenhe River, Luanhe River, Liaohe River, and Songhua River. The forests are mainly distributed in the northeast along a sand prevention belt in the south area along the desertification-control areas, and the mountainous area, occupying 4.7%. Built-up regions are scattered in plains, intersecting with cropland and grassland.  
Substantial LULC changes are expected to be observed in eastern and southwestern regions from 2010 to 2100. The environmental-oriented scenarios (i.e., scenario A1B and B1) aim to protect natural systems (e.g., grassland and forest) (Figure 3c). On the one hand, A1B is similar to B1 in the land conversion pattern that eastern cropland is projected to be transferred into grassland. Grasslands in A1B and B1 in 2100 account for 79.7% and 80.2%, respectively (Table 1). The forest is projected to be converted from cropland in the southwest and grassland in the southern margin. The proportion of forest at the end of the period reaches up to 19.8% and 22.4% in A1B and B1, respectively (Table 1).  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **Baseline A1B** & & **A2** & & **B1** & & **B2** & \\ \hline  & **2010** & **2050** & **2100** & **2050** & **2100** & **2050** & **2100** & **2050** & **2100** \\ \hline Cropland & 17.5 & 12.6(\(-\)28) & 5.1(\(-\)71) & 21.4(22) & 33.3(91) & 11.9(\(-\)32) & 1.9(\(-\)89) & 13.6(\(-\)22) & 26.0(49) \\ Forest & 4.7 & 5.6(20) & 19.8(324) & 3.8(\(-\)19) & 1.2(\(-\)74) & 6.4(37) & 22.4(380) & 5(7) & 2.9(\(-\)38) \\ Grassland & 74.4 & 79.7(7) & 73.5(\(-\)16) & 69.3(\(-\)7) & 60.8(\(-\)18) & 80.2(8) & 74.5(0) & 79.4(7) & 69.9(\(-\)6) \\ Water & 0.1 & 0.1(0) & 0.1(0) & 0.1(0) & 0.1(0) & 0.1(0) & 0.1(0) & 0.1(0) & 0.1(0) \\ Built-up & 0.6 & 1.2(90) & 1.2(90) & 3.6(471) & 4.6(630) & 0.9(43) & 0.9(43) & 0.8(27) & 0.9(43) \\ Bare land & 2.7 & 0.8(\(-\)71) & 0.2(\(-\)93) & 1.8(\(-\)34) & 0.1(\(-\)96) & 0.6(\(-\)78) & 0.2(\(-\)93) & 1.2(\(-\)56) & 0.2(\(-\)93) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Percentage of areas under different scenarios (unit: %). Figures in brackets represent changing percentage of future LULC (unit: %) compared to the year 2010 (baseline).  
Figure 3: Current (year 2010), future LULC maps (year 2050 and 2100), and land conversion maps from 2010 to 2100. (**a**) LULC map for year 2010; (**b**) Future LULC maps for each scenario. In the black frame of (**b**), the maps are arranged from left to right in order from 2050 to 2100, and arranged from top to bottom in order from A1B to B2; (**c**) Land conversions from 2010 to 2100 for each scenario. From top to bottom, the order is from A1B to B2. CROP = Cropland, FORE = forest, GRAS = Grassland, WATE = Water body, BUIL = Built-up, BARE = bare land.  
On the other hand, B1 shows more intensive conversions to ecological lands than those in A1B, which could be seen in the eastern region.  
The economically oriented scenarios (i.e. scenario A2 and B2) attempt to maximize the amount of human-used land (e.g., cropland) (Figure 3c). Cropland in the east is extensively reclaimed from grassland under both the A2 and B2 scenarios, reaching up to 21.4% and 26.0%, respectively. Especially in the A2 scenario, cropland converted from forest in the southern regions could also be observed and built-up expands dramatically in the central and western regions, occupying a large number of grasslands. It should be noted that under the four scenarios, bare land in the north-west (approximately north of the Lanzhou area on the map) is expected to be restored to grassland, especially in 2100.