# Desertification Mitigation in Northern China Was Promoted by Climate Drivers after 2000
## 5 Conclusions  
This study employed NPP as a quantitative indicator to monitor the desertification trend from 1984 to 2014 and to assess the relative contributions of climate drivers and human activity. The results show that 72.74% of the total area of the DPR in NC experienced desertification mitigation from 1984 to 2014. These areas were predominantly in the northern and northwestern regions. Meanwhile, the regions with desertification exacerbation accounted for 27.26% of the DPR. This was mainly observed in Otindag. The _SpnPP_ and _SthnPP_ indicated that climate drivers served as the primary factors influencing the desertification process: they contributed to 47.2% of mitigation and 48.5% of exacerbation, whereas human activity accounted for 39.6% of mitigation and 41.0% of exacerbation. The remaining 13.2% and 10.5% of the area were influenced by both human activity and climate drivers. A shift in desertification occurred around 2000, with mitigation appearing in most regions. Before 2000, nearly half of the DPR areas (49.27%) experienced mitigation, with human activity having a slightly stronger positive effect (44.8%) compared to climate drivers (40.9%). Since 2000, there has been substantial desertification mitigation (67.16%), with climate drivers becoming the dominant positive factor (66.8%). However, 32.84% of the DPR still experienced desertification exacerbation, of which human activity contributed 81.7%. In addition to the near-surface air temperature and surface evapotranspiration, precipitation is the primary climatic factor that has promoted the mitigation of desertification in the DPR of NC since 2000. The abnormal easterly winds caused by the phase changes of the AMO and PDO transport additional water vapor over Ala Shan, Hexi Corridor, and Ordos, thereby increasing precipitation, enhancing the climate's ability to affect vegetation, and helping to alleviate desertification, which is also influenced by human activity. While many ecological projects have helped to control its expansion, irrational land use persists. Although the impact of changes in climatic factors is stronger than that of human activity, human activity seems more controllable than climate drivers when changing desertification, even under unfavorable climatic conditions (i.e., increases in both the near-surface air temperature and evapotranspiration and decreases in precipitation), such as the situation in Ordos. Meanwhile, even when climatic conditions are favorable for desertification mitigation, irrational human activities can still cause desertification exacerbation, such as in Horqin. This study quantified desertification changes in the DPR of NC during the period of 1984-2014 and detected the main causes across different time periods and regions. The research results are beneficial for a deep understanding of desertification and the formation mechanism under the background of climate change, and these also offer a scientific foundation for the targeted management of desertification, with strategies tailored to specific temporal and regional contexts. The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/rs16193706/s1](https://www.mdpi.com/article/10.3390/rs16193706/s1)]([https://www.mdpi.com/article/10.3390/rs16193706/s1](https://www.mdpi.com/article/10.3390/rs16193706/s1)), Method S1: Detailed algorithms of the CASA model; Method S2: Detailed algorithms of the modified Thornthwaite memorial model; Method S3: Taylor skill score; Method S4: Detailed algorithms of the contributions of different climatic factors to PNPP; Note S1: Desertification-prone region (DPR) in Northern China. Figure S1: Flowchart of this study; Figure S2: Detailed flowchart for calculating ANPP, PNPP, and HNPP; Figure S3: The validation of the CASA model by GLASS data; Figure S4: Contribution of factors to desertification change but using Glass NPP; Figure S5: The same as Figure S4 but for different time periods; Figure S6: Contributions of climate change and human activities to different areas.