Characteristics of temperature change in China over the last 2000 years and spatial patterns of dryness/wetness during cold and warm periods

This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50-70-yr, 100-120-yr, and 200-250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3A degrees C and 0.7A degrees C, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870-2000, at a rate of 0.56A degrees +/- 0.42A degrees C (100 yr)(-1); however, temperatures recorded in the 20th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981-1100 and AD 1201-70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern: dry south of 25A degrees N, wet from 25A degrees-30A degrees N, and dry to the north of 30A degrees N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20th century warming can primarily be attributed to a mega El NiEeno-Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China.