A Two-Millennia Relationship Between Climate and Economic Data

By Craig D. Idso of Cato.

"Introducing their intriguing work, Wei et al. (2015) write that “investigating climate-society relationships has long been a hot topic,” noting that “many studies have demonstrated the important roles of climate change in facilitating the rise or fall of ancient communities.” However, they report that “intense arguments regarding the economic effects of global warming” remain to be clarified in such investigations.

Against this backdrop, Wei et al. set out to investigate the long-term relationship between the climate and economy of China. More specifically, they derived a 2,130-year long record of the Chinese economy based on 1,091 records extracted from 25 books on Chinese history and economic history, spanning the period 220 BC to 1910 AD. This new proxy was then statistically analyzed in conjunction with historical proxies of Chinese temperature and precipitation previously compiled by Ge et al. (2013) and Zheng et al. (2006), respectively. And what did that analysis reveal?

The three Chinese researchers found that warm and wet climate periods coincided with more prosperous and robust economic phases (above-average mean economic level, higher ratio of economic prosperity, and less intense variations), whereas opposite economic conditions ensued during cold and dry periods (where the possibility of economic crisis was “greatly increased”) (see Figure 1 below). They also report that temperature was “more influential than precipitation in explaining the long-term economic fluctuations, whereas precipitation displayed more significant effects on the short-term macro-economic cycle.”

In concluding their paper Wei et al. write that, “from a deep time perspective, our study may provide new insight into the current intense arguments regarding the economic effects of global warming.” Indeed it does; and that insight reveals a warmer (and wetter) climate favors economic prosperity. Given this data-derived relationship, why are the leaders of so many nations hell-bent on halting any future rise in global temperature, especially when two millennia of climate and economic data suggest such a rise would benefit the economy? As the late Casey Stengel would have said, “doesn’t anybody know how to play this game?”

Figure 1. Series comparison between economic fluctuations and climate changes in China from BC 220 to AD 1910. Panel a: Decadal temperature anomaly for all of China during the period AD 1–1910 (Ge et al. 2013); the red curve is the low-pass filtered series. Panel b: Decadal precipitation over eastern China during the period 101–1910 (Zheng et al. 2006); the blue curve is the low-pass filtered series. Panel c: Winter half-year temperature anomaly series for eastern China during the period BC 210–AD 1920 with a 30-year resolution (Ge 2011). Panel d: Decadal macro-economic series during the period BC 220–AD 1910 in China; the black curve is the low-pass filtered series. The red and blue bars indicate typical episodes of prosperity and crisis periods (respectively). The gray and white areas delineate cold and warm phases, respectively. Figure from Wei et al. (2015)."