Fig. 2: Observed nonlinear economic impact of the IOD.
From: Nonlinear country-heterogenous impact of the Indian Ocean Dipole on global economies
a Timeseries of Kenya’s GDP growth rate change from the IOD (black line) and the IOD index (bars). Change in GDP growth rate is calculated as the cumulative contemporaneous effect of an IOD event in year 0 and growth effects of IOD events in year -1 and -2. Gray shading indicates the 95% confidence interval based on the Bootstrap method (see “Bootstrap tests” in “Methods”). Strong pIOD (SON IOD index >1.5 s.d) and nIOD (SON IOD index < −1.5 s.d) events are marked as red and blue bars, respectively. b Nonlinear relationship between the IOD index and IOD-induced change in Kenya’s GDP growth rate shifted backward by one year (both shown in Fig. 2a), with shading indicating the 95% confidence interval based on the Bootstrap method. A quadratic fitting, in which GDP growth=constant + k×IOD + Ω×IOD2, is performed and the coefficient for the nonlinear term Ω is shown. c Relationship between teleconnection and the nonlinearity Ω for all countries. Dots on the fitted line are examples of some strongly affected countries. Shading indicates the 95% confidence interval based on the Bootstrap method. Asymmetric impacts between pIOD and nIOD render an economic loss from IOD cycles, which increases exponentially with teleconnection strength.
