## 5 Conclusions  
In this study, we analyzed the temporal-spatial variation of land development and degradation in China's coastal region from 1982 to 2015, using the LDDI index based on NDVI and GPP data and the residual analysis method. In addition, we quantitatively evaluated the relative contribution of the main driving factors to LDD and explored the impacts of climate and human factors. Our key findings are as follows:  
1. During the study period, the primary LDD process observed in China's coastal region was land development, with 62.47% of the area exhibiting significant changes in land development trends. In contrast, land degradation processes were observed in only 7.03% of the region, mainly concentrated in the YRD, north of TW, PRD, and northeast LN. 2. Compared to climate change factors, human activities have a stronger impact on the changes in the LDD process. During the study period, the contribution of human activities to the LDD process became increasingly evident, with their contribution to LDD changes exceeding 60% in most regions. About 25.76% of the study area was significantly impacted by human activities, with approximately 21.61% of the land mainly affected by land development. In comparison, land degradation accounted for only 4.15% of the total area, fragmented and distributed in the PRD, YRD, and northeastern LN. 3. In most land types, land development dominates the LDD process, with land development areas of croplands, forests, and impervious regions accounting for 63.21% of the total study area. Significant expansion trends (\(p<0.01\)) were observed in impervious, water, and forest regions within the study region, while wetlands, shrubs, grasslands, barren land, and croplands showed significant decreases (\(p<0.01\)). Over the past few decades, China's coastal region has experienced rapid urbanization, significantly converting arable land into construction land. Between 1985 and 2015, cropland area decreased by 13.2% (7.81 million ha), primarily converting into impervious and forest land. Notably, 91.31% of the converted impervious land originated from cropland. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/rs15092249/s1](https://www.mdpi.com/article/10.3390/rs15092249/s1)]([https://www.mdpi.com/article/10.3390/rs15092249/s1](https://www.mdpi.com/article/10.3390/rs15092249/s1)), Table S1: LDD processes in coastal China; Table S2: The change in effects of human activities on LDD; Table S3: Classification standard of LDD types; Table S4: Pearson correlation coefficients between LDDI and different extreme temperature indices: Table S5 Pearson correlation coefficients between LDDI and different extreme precipitation indices; Table S6: Summary of the planned timeframe, aims, and objectives of major Chinese sustainability programs; Table S7: Ratio (%) of land cover conversions from 1985 to 2015; Figure S1: Multi-year average of normalized SPP values; Figure S3: The proportion of different LDD change types among different LULC types; Figure S4: Heat map of the ratio (%) of LULC types transfer out and transfer in different provinces. Conceptualization, Y.L. ; methodology and data curation, Y.H. and J.Y. ; writing--original draft preparation, Y.H. ; writing--review and editing, Y.H. and G.L. ; visualization and supervision, Y.Z. and Y.L. All authors have read and agreed to the published version of the manuscript. The study was funded by the Open Research Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin (IWHR-SKL-KF202204), the Jiangsu Funding Program for Excellent Postdoctoral Talent (2022 ZB147), the Key Scientific and Technological Project of the Ministry of Water Resources, P.R.C. (SKS-2022001), the Systematic Project of Guangxi Key Laboratory of Disaster Prevention and Engineering Safety (2022 ZDK026) and TianHe Qingsuo Project special fund project in the field of climate, meteorology and ocean.