The paper submitted by Meister and colleagues presents the first comprehensive compilation and assessment of diatom oxygen isotope records in lake sediments (δ18OBSi). The authors have supplemented these data with additional lake basin parameters (such as catchment size and residence times). The manuscript first infers the spatial and temporal coverage of δ18OBSi records and then discusses common hemispheric trends on centennial and millennial time scales, with key results such as: - Common patterns for hydrologically open lakes in extra-tropical regions of the Northern Hemisphere. - Common trends during the Common Era and throughout the Holocene corresponding to known climatic epochs such as the Holocene Thermal Maximum, Neoglacial cooling, the Medieval Climate Anomaly and the Little Ice Age. This is a well-written manuscript that should make a valuable contribution to reconstructions of past climates.