Figure 2 : The rise and fall and rise again of dragons.

From: Here be dragons

Figure 2

The relative frequency of 'dragons' in fictional literature (thick red line), as determined as a unigram probability4, with two historical reconstructions of Northern Hemisphere temperature (decadal smoothing) shown in blue5 and purple6. Global temperatures have been measured since 1855 (thick black line5). Temperature anomalies represent deviations from the 1961–90 reference period. The rising incidence of dragons in the literature correlates with rising temperatures, and suggests that these fire-breathing lizards are being sighted more frequently. As a result, the large-scale 'Third Stir' is deemed to be imminent.