Coastal cliff research trends and future directions

Coastal cliffs are important landforms, acting as barriers to wave energy, sources of sediments, and records of interactions between continental and marine processes. However, they remain underrepresented in the scientific literature, especially in regions of the Global South. This study aims to characterize, through a systematic and bibliometric approach, the evolution of international scientific production on coastal cliffs in terms of volume, geographical distribution, themes, monitoring methods, and knowledge gaps, incorporating the Brazilian coast as a case study in the Southwestern Atlantic. A combined search in the Scopus and Web of Science databases initially resulted in 1,925 works, which were filtered to obtain a final sample of 511 articles published between 1972 and 2024, analyzed using the Bibliometrix package and its Biblioshiny interface. We evaluated temporal trends in publication, the most productive countries and journals, collaboration networks, and the diffusion of geotechnologies such as LiDAR, Unmanned Aerial Vehicles (UAVs), and Structure from Motion (SfM). The results indicate a sharp increase in production after 2000, a concentration of research in Europe and North America, and an underrepresentation of South America and Africa. Consolidated research fronts are observed around cliff erosion, slope stability, and geological risk, as well as emerging themes related to numerical modeling and machine learning. In Brazil, there is a low number of indexed studies, a concentration of investigations in a few coastal sectors, and limitations in funding and high-resolution time series, which contribute to the underestimation of the importance of cliffs in the Southwestern Atlantic. Taken together, the results reveal a North–South geographic imbalance in publications, a limited understanding of the forcing mechanisms of cliff erosion, and a mismatch between high spatial precision and low temporal resolution of data, highlighting the need to expand monitoring and better integrate these environments into coastal management strategies and climate change adaptation.