Deciphering climatic history from lake sediments

Reconstructing climate from lake sediments can be challenging, because the response of lakes and various components of lake systems are mediated by non-climatic factors, such as geomorphic and hydrologic stetting. As a result, the magnitude of lake response to climatic forcing may be non-linear. In addition, changes in the lake system associated with the aging process or non-climatic influences may alter the response to a given climate perturbation. These non-linear and nonstationary characteristics can produce spatial heterogeneity in the pattern and timing of inferred change. One approach for generating regionally robust climatic interpretations from lakes is to increase coordinated efforts to generate and synthesize large data sets, so that localized influences can be more clearly distinguished from broad-scale regional patterns. This approach will be most successful for evaluating climate variation at multi-decadal or longer temporal scales; the climatic interpretation of higher frequency limnological variation can be more complicated, because of dating uncertainties and differential response times of individual proxies and systems.