Glaciers provide iconic illustrations of past climate change, but records of glacier length fluctuations have not been used systematically to test the ability of models to reproduce past changes. One reason is that glacier length depends on several complex factors and so cannot be simply linked to the climate simulated by models. This is done here, and it is shown that the observed glacier length fluctuations are generally well within the range of the simulations.

This study presents organic acid levels in an ice core from Svalbard over the past 800 years. These acids are produced from wildfire emissions and transported as aerosol. Organic acid levels are high early in the record and decline until the 20th century. Siberia and Europe are likely the primary source regions of the fire emissions. The data are similar to those from a Siberian ice core prior to 1400 CE. The timing of the divergence after 1400 CE is similar to a shift in North Atlantic climate.

The climate of the last glacial period was frequently interrupted by rapid warming events, the cause of which is still unknown. One open question is whether the occurrence of events is random or externally controlled. We studied the temporal characteristics of warm and cold phases using statistical null models and find that they are well described as random processes modulated by two different external climate factors. This may help distinguish physical mechanisms for rapid climate change.

We explain the procedure used to attain a high and consistent level of data stewardship across a special issue of the journal Climate of the Past. We discuss the challenges related to (1) determining which data are essential for public archival, (2) using data generated by others, and (3) understanding data citations. We anticipate that open-data sharing in paleo sciences will accelerate as the advantages become more evident and as practices that reduce data loss become the accepted convention.

Palaeoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid climate change, but only a small proportion of the ocean is suitable for such reconstructions using the existing state of the art, i.e. the age-depth approach. We use dual radiocarbon (¹⁴C) and stable isotope analysis on single foraminifera to bypass the long-standing age-depth approach, thus facilitating past ocean chemistry reconstructions from vast, previously untapped ocean areas.