Table 1.

GCA for each of the linkages shown in Fig. 2 (SI Appendix, Text section 2.1)

Causal linkage (null hypothesis)FP
Climate change does not Granger-cause bio-productivity207.4850.000*
Bio-productivity does not Granger-cause agricultural production7.4400.007
Agricultural production does not Granger-cause FSPC9.8340.002
War does not Granger-cause population391.8050.000*
Epidemics does not Granger-cause population103.0540.000*
Famine does not Granger-cause population155.7360.000*
Population does not Granger-cause agricultural production5.7310.017
Population does not Granger-cause FSPC67.6640.000*
FSPC does not Granger-cause famine10.3070.000*
Famine does not Granger-cause nutritional status2.1390.009
Nutritional status does not Granger-cause epidemics2.3450.004
FSPC does not Granger-cause social disturbance1.9710.024
Social disturbance does not Granger-cause war3.2560.000*
Social disturbance does not Granger-cause migration1.7860.037
War does not Granger-cause migration2.2500.006
FSPC does not Granger-cause migration2.1640.008
Migration does not Granger-cause epidemics1.8350.031
  • *Significant at 0.001 level (2-tailed) (P < 0.001).

  • Significant at 0.01 level (2-tailed) (P < 0.01).

  • Significant at 0.05 level (2-tailed) (P < 0.05).