The financing plan, which calls for $300 billion per year in support for developing nations, was immediately assailed as inadequate by a string of delegates.

In the wee hours Sunday at the United Nations climate talks, countries from around the world reached an agreement on how rich countries can cough up the funds to support poor countries in the face of climate change.

The deal embodies the disappointment and distrust that many developing nations have voiced at these annual climate negotiations. After three decades, the talks have put the planet on a safer trajectory in terms of its overall temperature rise. And yet ...