Lakes are distributed widely across the globe, and depending on their location, they can be particularly sensitive to changing climate.  For example, global warming is having a significant impact on lakes in polar and alpine environments, while variation in rainfall patterns impacts on lakes in semi-arid regions.  In order to understand the climate history that can be obtained from lakes, we need to briefly consider how temperature and precipitation affect different types of lakes.   In cold, polar-regions, lakes are normally covered by ice for many months of the year.  During spring, the ice melts and winds help mix the water up, which also ensures...