FIG 1.

(A) Frequency distribution of the number of factors of global change included in experimental studies between 1957 and 2017. (B) Numbers of experimental studies that included a given number of factors over the past 50 years. For comparison, the dashed gray line (right y axis) represents the number of published articles per year for the Web of Knowledge category “ecology.” (C) Numbers of papers that included a given global change factor for studies with one to four combined factors. (D) Network graph depicting the co-occurrence of global change factors in experimental studies, where circle size represents the frequency with which the driver was included in the studies, and line thickness represents the frequency with which the drivers were tested as combinations. Reproduced from reference 6 with permission from AAAS.