The central idea of the lifeboat methaphor is wealthy nations are in the lifeboat while poor nations are drowning in the water.
Lifeboat ethics refers to a metaphor for resource distribution proposed by the ecologist Garrett Hardin in 1974.
Hardin's metaphor describes a lifeboat bearing 50 people, with room for ten more. The lifeboat is in an ocean surrounded by a hundred swimmers. The "ethics" of the situation arise from the dilemma of whether and under what circumstances swimmers should be taken aboard the lifeboat.