**5. Conclusions**

In this study, we evaluated the performance of CMIP6 models in simulating LAI and the LAI trend during the growing season of the Tibetan Plateau over the period 1981–2014, compared with the GLASS LAI. We found the following:


**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/rs14184633/s1. Figure S1. The relative bias of the monthly mean LAI with simulations and observations; Figure S2. The bias of the monthly mean linear trend with simulations and observations; Figure S3. Spatial distributions of the simulated LAI during the growing season; Figure S4. The distribution of bias, relative bias and RMSE between the simulated and observed LAI with 35 CMIP6 models for different vegetation types; Figure S5. The area-averaged linear trend of simulated and observed LAI the during the growing season (*p* < 0.05); Figure S6. Spatial distributions of the simulated LAI linear trend during the growing season; Figure S7. The distribution of bias and RMSE between the simulated and observed LAI trend with 35 CMIP6 models for different vegetation types; Figure S8. The monthly LAI of 35 CMIP6 models from 1981 to 2014; Table S1. Summary of evaluation metrics and error ranking for models with the performance to simulate the LAI of Tibetan Plateau during growing season in1981–2014; Table S2. Summary of evaluation metrics and error ranking for models with the performance to simulate the LAI trend of Tibetan Plateau during growing season in1981–2014.

**Author Contributions:** Writing—original draft preparation, J.L. and Y.L.; writing—review and editing, J.L. and Y.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Strategic Priority Research Program of Chinese Academy of Sciences gran<sup>t</sup> number No. XDA20050102, XDA23060601, and the National Natural Science Foundation of China gran<sup>t</sup> number No. 41975135.

**Data Availability Statement:** The study did not report any data. **Acknowledgments:** Thank you to the anonymous reviewers who gave useful advice and made our article more organized. This study was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDA20050102, XDA23060601) and the National Natural Science Foundation of China (No. 41975135). We are grateful for the data set of the Tibetan Plateau Boundary high frequency (HF) and the 1:1 million vegetation data set in China provided by the National Tibetan Plateau Data Center (http://data.tpdc.ac.cn, accessed on 9 December 2021). We thank the Beijing Normal University for providing the Global Products of Essential Land Variables (GLASS). We acknowledge the World Climate Research Programme, which, through its Working Group on Coupled Modelling, coordinated and promoted CMIP6. We thank the climate modeling groups for producing and making available their model output, the Earth System Grid Federation (ESGF), for archiving the data and providing access, and the multiple funding agencies that supported CMIP6 and ESGF.

**Conflicts of Interest:** There is no conflict of interest.
