This paper introduces the ClimeApp web application. The app provides quick access to the ModE-RA global climate reanalysis. Users can calculate and plot anomalies, composites, correlations, regressions and annual cycles across three different datasets and four climate variables. By re-examining the 1815 Tambora eruption, we demonstrate how combining results from different datasets and sources can help us investigate the historical palaeoclimate and integrate it into human history.

We reconstruct global hydroclimate anomalies for the past 21 000 years using a data assimilation methodology blending observations recorded in lake sediments with the climate dynamics simulated by climate models. The reconstruction resolves data–model disagreement in east Africa and North America, and we find that changing global temperatures and associated circulation patterns, as well as orbital forcing, are the dominant controls on global precipitation over this interval.