The Niger, by contrast, is shrinking. Nine West African leaders agreed this week on a 20-year plan to rescue it by reforestation and removing silt.

• 然而，干涸中的尼日尔河却是反例。为拯救它，9位西非国家领导人于本周共同签署了一项20年重新造林和清除淤泥的修复计划。