Abstract
Global climate variability is a well-documented fact; however, the human contribution to climate change is now being vigorously debated. Therefore, a better understanding of past natural climate variability may help to establish the actual anthropogenic contribution to the observed climatic trend.
A variety of high-resolution proxies now exist for documenting climate variability that has occurred in the northern hemisphere over the last 10 ka. In contrast, high-resolution paleoclimate records are more limited for regions such as high altitudes in the Andes/South America.
However, many regions of the Andes contain a rich, but as yet overlooked, paleoclimate archive in the form of thick peat deposited in situ by the Distichia plant. In our study, based on altitudinal transect from the Peruvian Andes, we found a statistically significant and strong relationship between the stable carbon isotope composition of Distichia and air temperature (R=0.92 p{0.01).
We also confirmed good preservation of relative differences in the original stable carbon isotope composition in peat derived from this plant. Our calibration showed that a decrease of ~0.97+-0.23%o in the stable carbon isotope composition of Distichia peat reflects a 1oC increase in mean air temperature of the growing seasons.
This relationship can be used as a new high-resolution proxy for reconstruction of paleotemperature variations over the past several thousand years in the Andes Mountains based on Distichia peat cores.