Unprecedented early summer warming recorded in tree rings on the central eastern Tibetan Plateau over the past three centuries

The Tibetan Plateau is a fast-warming region in China, whereby the rapid temperature increase affects regional ecosystems and mountain glaciers significantly. Long-term high-quality temperature data are urgently needed to understand how temperature has changed in the past several centuries and the underlying driving forces. In this study, we developed two tree-ring width chronologies that are more than 300 years. The two chronologies are highly consistent, indicating that the two sites were seldom disturbed by human activities. A robust tree-ring width chronology was developed using all the samples of the two sites, which represents June-July mean temperature according to statistical correlation analysis. The recent two decades are the warmest over the past three centuries, showing a regional temperature response to global warming largely contributed by human influence on climate system. Multi-decadal temperature variations in the study area have been closely linked with the Atlantic Multidecadal Oscillation in the past three centuries, highlighting the Atlantic influence on regional climate change on the central eastern Tibetan Plateau in warm seasons.