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The present study aims to compare quantitatively the similarities and differences of transmission processes extending from climate change to grain harvests and economies (macro-economy and fiscal balance) between the Han (206 BC–AD 220) and Tang (AD 618–907) dynasties of China. It is found that both the Han and Tang periods displayed close positive correlations among temperature, grain harvest, macro-economy and fiscal balance and conveyed a positive feedback–oriented transmission pattern with the upgrade of climatic impact level from grain harvest to economic system. Compared with the Han period, the overall linkages among indicators weakened during the Tang period, particularly for the correlation between grain harvest and fiscal balance. The mean temperature during the Tang period was slightly higher but had greater multidecadal variability, coinciding with better performance (and less variations) of macro-economy and fiscal balance (particularly for cold units) and higher variations of grain harvest. It displayed relatively little difference for the main pathways that could be interpreted as climatic impacts during the warm units between the Han and Tang periods, and both approximately 33% of the decades for warm units (100%) ending with fiscal balance/surplus were more likely to be associated with the impacts of temperature change. The difference mainly lies in cold units in the links of ‘cold → poor harvest’ and ‘poor harvest → macro-economic depression’ through the pathway of ‘cold → poor harvest → macro-economic depression/normal economy → fiscal deficiency’. Overall, macro-economy and fiscal system of the Tang period displayed less sensitivity to temperature change and agriculture production in cold period. Those patterns might be related with the unique socio-economic situations such as agricultural fragmentation, southward shift of economic resource and tax system reform during the later Tang Dynasty.

Investigations of the relationships between climate and human history often place more emphasis on the science of climate change than on understanding human socio-economic processes, and therefore suffer from superficial results and an unbalanced perspective. This is partly due to the lack of high-resolution data concerning long-term socio-economic processes. Here, we base our study of climate and society on a series of 2130-yr-long economic proxy data from China with decadal resolution. The economy was associated significantly with temperature and precipitation at the two predominant bands of 100 and 320 yr. The phase transition of economic states was influenced positively by long-term temperature change combined with triggering effects of short-term changes in precipitation. However, climatic impact on economy should not be recognized as simple causality but some driving-response relation coupled with meditation by human agency at multiple scales. A model of ‘adaptive cycles’ implies, in relative to the developing phases, climate–economy relationship during the declining phases was more easily moderated by slower processes like rigidity and faster processes like unrest. From a more-macro perspective, climatic driving for the macro-economic cycles was moderated by larger and slower processes like social memory, spatial shifting of key economic areas, and social–technical advance.

The relation between climate change and historical rhythms has long been discussed; however, this type of study still faces the lack of high-resolution data of long-term socio-economic processes. In this study, we collected 1101 items of direct and proffered evidence from 24 Chinese fiscal and economic history books written by leading contemporary scholars. By analysing the semantics of words, we reconstructed a 2130-year-long fiscal sequence with decadal resolution to express the phase transition of fiscal soundness for approximately 21 dynasties in China. Our reconstruction shows four relatively sufficient stages and three relatively deficient stages, with several secondary stages lasting 60 or 160 years on average within each large stage, from 220 bc to ad 1910. Then, the fiscal association with climate change was analysed. The results show that the fiscal crisis was more likely to occur in cold-dry climatic scenarios. Both temperature and precipitation displayed more significant effects on the fiscal fluctuation within the long term, particularly for temperature. In short, fiscal decline had a 10-year lag in response to decreasing precipitation, whereas influence of decreasing temperature on the fiscal balance might be through amplifying already deteriorating fiscal conditions. Regional differences existed in the influence of precipitation on the fiscal balance. The precipitation in the Northern China Plain and in the Jiang-Huai area had more significant effects on the fluctuation of the dynastic fiscal balance than on that in the Jiang-Nan area. In particular, the dynastic finance was more sensitive to the change in the precipitation in the Northern China Plain because of its special geographical, economic and social backgrounds.