Although regional studies and projections suggest the deterioration of estuaries as a consequence of climate change, it is still difficult to fully understand the importance of such changes in estuarine systems. This limitation is particularly important considering their high dynamism and the lack of temporally extended in situ databases with a good spatial coverage for these systems worldwide. Furthermore, contradictory patterns have been observed across the globe. Motivated by these issues, in this study we question the availability of in situ observational evidence of climate change in estuarine systems through a detailed meta-analysis of existing publications. A topic-related search considering the outputs of the Web of Science library was conducted in order to obtain a characterization of the existing studies on climate change in estuarine systems. Results confirmed that climate change has increasingly been studied since 2000 and that marine climate change constituted the focus of 9.69 % of those studies. From these, only 9.30 % encompassed estuarine studies and just 1.13 % used in situ observations from estuarine systems (i.e., 0.11 % of the total climate change publications). Reanalysis products were the most used tools to assess changes in estuarine systems and sea temperature was the most analyzed variable. These results highlight the need to further address such questions using in situ observational data and to implement long-term observatories to fully identify evidence of climate change in estuarine systems, supporting modelling approaches and promoting the development of effective mitigation plans. Display omitted •Data is lacking to fully understand the importance of climate change in estuaries.•Only 0.11 % of climate change studies focus observational changes in estuaries.•Water temperature is the most studied variable in the literature focusing estuaries.•Numerical models are the most used approach to assess these type of changes.•We highlight the urgent need to implement long-term observatories in estuaries.