evidence: Tide gauges and satellite altimetry are complimentary datasets, and both are necessary to observe the complete spectrum of processes that lead to sea level variability. Since 1993, satellite altimeters have provided continuous, near-global (± 66ºN) measurements of sea surface height. These measurements provide definitive estimates of global mean sea level rise during recent decades (~3.2 mm/year from 1993 to present) with much less uncertainty than the global rate derived from tide gauges. Tide gauges, on the other hand, provide the long-term context that is necessary to interpret the short satellite record. [...] The Permanent Service for Mean Sea Level (PSMSL; http://www.psmsl.org/) provides a global archive of monthly and annual quality-controlled sea level records. Based on the quality of the benchmark history, PSMSL categorizes tide gauge records into one of two datasets: the Revised Local Reference (RLR) dataset, and the Metric dataset. Records in the RLR dataset have a well-defined and internally consistent benchmark history, which makes these records suitable for studies of long-term sea level change. The Metric records, on the other hand, are missing complete benchmark histories, and PSMSL advises that these gauges are not to be used for climate studies.