# Long-Term Analysis of Wave Climate and Shoreline Change along the Gulf of California
## 6 Conclusions  
Understanding the long-term variability of the wave period, wave height, wave power and shoreline change will contribute to more reliable assessments of CC's impact on the coast. To date, a regional and long-term perspective study of the wave and shoreline dynamics in the GC was not available, which limited the effectiveness of adaptation strategies. These variabilities were analyzed in the present work using time series of wave data from the ERA5 dataset and historical Landsat images from the USGS.  
The results indicate that mean and extreme waves have been becoming more energetic over the years in the GC. The largest increasing trend in wave energy was observed at the middle part of the Gulf, followed by the upper Gulf and, finally, the lower Gulf. The wave height was found to increase in the entire Gulf, while the long-term trend of the wave period was seen to decrease in the lower and middle Gulf and, in turn, was shown to increase in the upper Gulf. This discrepancy calls for further research including in situ measurements. Regarding the long-term coastline change, two-thirds of the  
Figure 8: Example of the impacts of tropical cyclones and cold fronts on the GC coast: (**a**) Mazatlan beach in Sinaloa, affected by cyclone Willa in 2018; (**b**) Altata beach in Sinaloa, affected by cyclone Bud in 2018; (**c**) Las Glorias beach in Sinaloa, affected by cyclone Odile in 2014; (**d**) Las Bocas beach in Sonora, affected by cold front passages between October 2015 and March 2016. Source: Google Earth and newspapers Noroeste, El Universal and La Pared.  
GC coast was found to suffer erosion. Erosional hotspots were identified on the coastal fringes on the northern and southern coasts of Sonora, on the northern coast of B.C. and along the coast of Sinaloa. Intervention should be then prioritized in those coastal fringes. Although this paper did not examine the exact evidence for coastal forcing as a driver of the observed shoreline displacements, a literature review allows arguing that they are a response to the combination of the effects of natural processes with those of human activities and climate change.  
The results of this paper present clear relevance for coastal risk management policies and should be incorporated into coastal climate change impact assessments for the development of local-level adaptation plans in the GC. Furthermore, additional research on other trends in oceanic forces that were not addressed in this paper such as storm waves and storm surges is encouraged.  
This paper demonstrates that a long-term analysis of wave climate and shoreline change using Interim ERA5 reanalysis wave data and historical Landsat images can be a reliable approach for a coastal environment with limited observational data.  
Conceptualization, C.F.-O., Y.Z.-M., M.E. and E.M.; methodology, C.F.-O., Y.Z.-M., W.P.-R., S.M.-A. and Y.R.-C.; formal analysis, C.F.-O., Y.Z.-M., W.P.-R. and S.M.-A.; investigation, C.F.-O., Y.Z.-M., W.P.-R. and S.M.-A.; writing--original draft preparation, C.F.-O., Y.R.-C., M.E. and E.M.; writing--review and editing, C.F.-O., Y.R.-C., M.E. and E.M. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Autonomous University of Sinaloa under research grant number PROFAPI2014/073.  
The authors are very grateful to [PERSON] for his helpful and unselfish support in reviewing this paper.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.