Proxy climate indicators from Arctic lakes

To understand the modern Arctic system and its current unprecedented change requires the long-term perspective of the natural variability that can only be gained through proxy records. Lakes are sensitive to climatic changes because small shifts in climate directly impact the heat and water balance of lakes, and indirectly impact the physical and ecological processes of their catchments, which can result in major shifts in limnology.

Reconstructing past climate from lake sediment relies on a range of proxy indicators. The multi-proxy approach afforded by paleolimnological studies provides insights into the array of climate state variables through which climate change is manifested. Most of the studies in this project rely on sedimentological or biological indicators. These including: varve thicknesses, chironomid assemblages, pollen spectra, biogenic-silica content, diatom floras, and oxygen isotopes. These proxies primarily attest to changes in past summer temperatures, the main control on a range of physical and biological processes in lakes at high latitudes. Some reflect other aspects of the climate system, including nutrient availability and storm-track trajectories.