Recent interest in varved sediments has expanded considerably, since they can provide an accurate chronology for paleoclimatic reconstruction and can be found in various environments around the globe. A varve is a lamina or a sequence of laminae deposited in a body of still water within a year's time. Proxy data, such as pollen, diatoms, stable isotope geochemistry and microchemical analysis, retrieved from such laminated records can be temporarily constrained. Also, the varves themselves contain climatic information.
Generally in order to validate climate models, especially in terms of their ability to simulate short-term environmental changes such as El Niño, it is important to test them against the past climate record. Such testing is usually restricted to instrumental climate data. However, high-resolution records (such as tree rings, banded corals, and ice cores, as well as varved sediments) can provide annually resolved paleoclimatic information for longer periods of time.