Faced with what they see as an existential threat, leaders from low-lying and island nations implored rich countries at the United Nations General Assembly this week to act more forcefully against a warming planet.

The failure by developed economies to effectively curb their greenhouse gas emissions contributes to rising sea levels and especially imperils island and low-lying nations at the mercy of water.

¡°We simply have no higher ground to cede,¡± Marshall Islands President David Kabua told leaders in a pre-recorded speech at the high-level gathering on Wednesday. ¡°The world simply cannot delay climate ambition any further.¡±