In the context of a warming climate, mountain environments are especially vulnerable to a change in the risk pattern. Our study focuses on the past evolution of wet avalanches, likely triggered by warmer temperatures destabilizing the snow cover. In the last 3300 years we observed an increase of wet avalanche occurrence related to human activities, intensifying pressure on forest cover, as well as favorable climate conditions such as warmer temperatures coinciding with retreating glacier phases.

We present two new palaeoclimatic records for the central Maya lowlands, adding valuable new insights to the impact of climate change on the development of Maya civilisation. Lake Tuspan's diatom record is indicative of precipitation changes at a local scale, while a beach ridge elevation record from the world's largest late Holocene beach ridge plain provides a regional picture.

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.