Over time, some of the hundreds of billions of dollars the poorer countries are demanding will begin to flow, as global carbon markets become established and governments in rich countries begin to open the spigot of public spending.
But in the meantime, the industrialized countries have proposed a relatively modest fund of about $10 billion a year for each of the next three or four years to help poorer countries adapt. Even that effort remains the subject of conflict over which countries should contribute how much, what body should oversee the spending and how to determine which projects qualify for finance.
President Obama’s spokesman said last week that the president supported a short-term fund to aid developing nations and that the United States would pay “its fair share.” In many multilateral efforts, the United States picks up a quarter to a third of the tab.
“Providing this assistance,” the White House statement said, “is not only a humanitarian imperative — it’s an investment in our common security, as no climate change accord can succeed if it does not help all countries reduce their emissions.”
The money would be used to help developing nations reduce emissions by switching to renewable energy sources like wind and solar and by compensating landowners for not cutting down or burning forests, a major source of carbon dioxide emissions. Other funds might be used to adjust to effects of a changing climate, like rising sea levels, by building flood walls or relocating settlements to higher ground.
Mr. Obama will travel to Copenhagen on Dec. 18 to attend the final day of the meeting, a sign that the White House believes that a far-reaching accord, including deals on some of the sticky financial issues, is possible.
“This is the question that is being posed in Copenhagen,” said Robert N. Stavins, director of the environmental economics program at Harvard University. “How much money do the developed countries have to put on the table to bring developing countries into the conversation?”
Mr. Stavins said that the bulk of the money would have to come from private investment because, he said, it was “inconceivable” that the governments of the wealthy countries would come up with adequate financing and also because private entities spent money much more efficiently.
The climate and energy legislation passed by the House in June sets aside roughly $8 billion a year for assistance to developing countries by 2030, Mr. Stavins said. That figure, he suggested, represents the upper limit of public financial support from the United States.
The perspective from the developing world is, not surprisingly, somewhat different.