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. 2007 Nov 28;104(49):19214–19219. doi: 10.1073/pnas.0703073104

Fig. 2.

Fig. 2.

Paleo-temperature variation and its impact on Europe and China, A.D. 1500–1800. (A) Temperature anomaly (°C) in the NH (17). (B–E) European data are in green and Chinese data are in red. The data are in normalized units that indicate the relative amplitude of change only. (B) Detrended estimated values of agricultural production (solid lines) and detrended grain yield ratio in Europe (green-dotted curve) (18). The estimated values of agricultural production are calculated by dividing population size by food price. (C) Detrended population size (solid lines) and population growth rate (dotted curves) (22, 24). (D) Detrended wheat price index in Europe and detrended rice price in China (41, 42). (E) Detrended total war frequency (‖ and ref. 40). All data are smoothed by 40-year Butterworth low pass filter. All of the dotted curves correspond to the right y axis.