Fig. 6: Global distribution of sustainability index (SI) and corresponding development stage of Golden Inland Waterways (GIWs) in 2015 and 2050.

a SI of global GIWs in 2015. b SI of global GIWs in 2050 under the ER invariant scenario. c SI of global GIWs in 2050 under the scenario where adjustments are made to ER aiming at improving sustainability. Red-to-blue gradient indicates the increasing SI of GIWs. GIWs are considered as achieving low, middle, and high levels of sustainability when SI < 0.5, 0.5 < SI < 0.7, and SI > 0.7. Source data are provided as a Source Data file.