A biologic or geologic structure of known age from which information on past climate may be extracted; may also be used with reference to climate information extracted from historical documents. Proxy climate records are of use for times and places lacking instrumental records. Examples include fossil species assemblages from rocks, geomorphic structures, the isotopic or species composition of marine or lacustrine sediments, the isotopic and other chemical composition of polar and very high elevation ice, and the structure and chemical composition of annual growth rings in trees and growth bands in corals.