## 5 Conclusions  
* Based on four state-of-the-art GPP datasets, we evaluated the performances of the GPP products against the EC data to detect the long-term trends in the GPP and their resilience to drought disturbance in the Middle East for the period of 1982 to 2016. Overall, the main results of this research can be summarized as given below. * The GPP dataset validation demonstrated a good agreement between the GLASS-GPP and EC-GPP datasets, while a low performance was noticed for the other products. * The M-K test of the annual variability in GPP presented a significant increasing trend at the pixel scale, specifically in the northern parts. Generally, the temporal trend of the regional carbon stocks (in PgC yr\({}^{-1}\)) in the Middle East showed an increase during the studied period for all the products except the FluxCom model. The highest increasing trends in the GPP value were obtained from the VPM model during the 2000-2016 period, while the lowest increasing trends in the GPP were detected by the GIMMS model. In contrast, a slightly decreasing trend was obtained by the FluxCom model. * The trend patterns in several GPP datasets were somewhat homogeneous for some models regardless of the magnitude of the trend and where the r correlation value between the VPM-GPP slopes and the GIMMS-GPP slopes was high. Other models such as the FluxCom-GPP and the GLASS-GPP had slope patterns that were very different. * Based on the annual values of the SEDI, a total of six significant drought events occurred in 1985, 1989-1990, 1994, 1999-2001, 2008, and 2015. The 2000 severe, extreme, and very extreme drought classes covered roughly 42% of the total area. * The results indicated that the FluxCom-GPP and VPM-GPP models were more sensitive to SEDI variability. Although the spatial distribution of the GPP response patterns to dry-wet conditions of the SEDI was somewhat similar and coherent among some models such as GLASS-GPP and FluxCom-GPP, the pairwise comparison among the other GPP models was less coherent (e.g., the FluxCom and VPM models). * Based on the high-resolution output of GLASS-GPP, the resilience of the ecosystem to drought disturbance was studied. Most of the ecosystems in the study area showed a high ability to tolerate extreme drought while maintaining the normal pattern and trend in GPP under severe to extreme conditions. The area that was not resilient to drought was mostly in the northern part of study area, which made up 49.7% of the total area. In general, the climate dynamic under global warming will cause high-risk drought occurrences in the Middle East's ecosystems. Drought management at the regional level necessitates the use of indices that improve drought monitoring both temporally and geographically, thereby resulting in suitable decisions that help mitigate the drought in the region. For several reasons, the formulation and implementation of environmental policies on the regional and national levels, including declaring an urgent plan to reduce humans' CO\({}_{2}\) emissions, has become a critical issue. A plan to transition to the \"post-carbon economy\" and pursue \"carbon neutrality\" is also required to balance those emissions; this can be done by reducing forest degradation, establishing afforestation and reforestation projects, and preserving the ecosystem in the long-term. Conceptualization, K.A. ; methodology, K.A. ; software, K.A. ; formal analysis, K.A. ; investigation, K.A. ; data curation, K.A. ; writing--original draft preparation, K.A. and A.E.K. ; writing--review and editing, S.M., S.S.S., A.K.S., A.A., B.B. and A.E.K. ; visualization, K.A. ; supervision, S.B. All authors have read and agreed to the published version of the manuscript. This work was supported by the National Natural Science Foundation of China (grant numbers 41971340 and 41271410) and the RESEARCHERS SUPPORTING PROJECT, grant number RSP-2021/296, King Saud University, Riyadh, Saudi Arabia.