Response of climate to solar forcing recorded in a 6000-yearδ18O time-series of Chinese peat cellulose

Abstract

Previous studies have shown that the oxygen isotope ratio (δ18O) of plant cellulose can serve as a sensitive proxy indicator of past climate, but its application has mainly been restricted to tree-rings. Here we present a 6000-year high-resolutionδ18O record of peat plant cellulose from northeastern China. Theδ18O variation is interpreted as reflecting changes in regional surface air temperature. The climate events inferred from the isotope data agree well with archaeological and historic evidence. The record shows a striking corre spondence of climate events to nearly all of the apparent solar activity changes characterized by the atmospheric radiocarbon in tree-rings over the past 6000 years. Spectral analysis of theδ18O record reveals the periodicities of around 86, 93, 101, 110, 127, 132, 140, 155, 207, 245, 311, 590, 820 and 1046 years, which are similar to those detected in the solar excursions. We consider these observations as further evidence for a close relationship between solar activity and climate variations on timescales of decades to centuries. Our results also have implications for distinguishing between natural and anthropogenic contributions to future climate change.