President Barack Obama’s latest announcement on his trip to Copenhagen demonstrates two things. First, he’s listening to the environmental community. Second, he and his advisors need to pay much closer attention to the politics and sensitivities of global climate change as representatives of 192 nations gather in Copenhagen over the next two weeks.

The White House announced Friday that Obama will appear at the 15th Conference of the Parties (COP-15) on Dec. 18, the final day of negotiations. On that new schedule, he will joint a large number of world leaders attending COP-15 as negotiations reach a climax during the conference’s last several days. As of Dec. 7, the opening day of the conference, 105 international leaders were scheduled to attend, representing 82 percent of mankind, 89 percent of the world's GDP and 80 percent of the world's current greenhouse gas emissions.

Obama also announced the United States pledges to pay its “fair share” of financial assistance from developed nations to help emerging economies reduce their greenhouse gas emissions and adapt to the impacts of climate change. Obama has consulted with the leaders of Australia, Great Britain, France and Germany, the White House said, and concluded “there appears to be an emerging consensus that a core element of the Copenhagen accord should be to mobilize $10 billion a year by 2012 to support adaptation and mitigation in developing countries, particularly the most vulnerable and least developed countries that could be destabilized by the impacts of climate change.”

In addition, the White House said, the discussions in Copenhagen must address long-term financing for developing nations to deal with mitigation and adaptation.

On Nov. 25, Obama said he would appear at COP-15 on Dec. 9. He also announced America’s goal for greenhouse gas reductions – “in the range” of 17 percent by 2020 compared to 1990.

The president’s original plan was criticized by several U.S. environmental organizations for two reasons. First, by showing up when other world leaders had not yet arrived, it appeared Obama was stopping in Copenhagen not to take part in substantive negotiations, but merely for a photo op on his way to accepting his Nobel Prize in Oslo a day later. Second, the U.S. position did not address the important issue of financial assistance to developing countries – a key sticking point in climate negotiations so far.

Obama and several other international leaders lowered the world’s expectations for Copenhagen several weeks ago when they said there were too many unresolved issues to expect that COP-15 would end with a binding global agreement to cut emissions. The most recent White House position has been that each nation should commit to its own climate action plan at Copenhagen, with an international deal to follow 6 to 12 months later.

The key question is whether Obama’s change of plans signals new optimism that an international treaty will emerge at Copenhagen, or whether the White House is simply correcting the mis-steps in its Nov. 25 announcement. At minimum, the President’s change of plans indicates he is more sensitive now to the importance of his participation at COP-15 and to the United States’ obligation to help developing nations deal with climate change.