Evidence for climatic change is taken from a variety of sources that can be used to reconstruct past climates. Reasonably complete global records of surface temperature are available beginning from the mid-late 19th century. For earlier periods, most of the evidence is indirectâclimatic changes are inferred from changes in proxies, indicators that reflect climate, such as vegetation, ice cores,dendrochronology, sea level change, and glacial geology.Climate change in the recent past may be detected by corresponding changes in settlement and agricultural patterns.Archaeological evidence, oral history and historical documents can offer insights into past changes in the climate. Climate change effects have been linked to the collapse of various civilizations.
Last date updated on July, 2014