On Monday Reuters broke the story that U.N. Secretary-General Ban Ki-moon is organizing a summit in New York next month, where he hopes to get heads of state from major greenhouse-gas emitters (the U.S., China, and India) to talk about climate action plans. (Grist reported on the first hints of such a conference a few weeks back.)

Ban seems to think the timing is right for two reasons: First, he wants to meet before the April G20 meeting of wealthy countries and key developing nations so that the global financial crisis doesn’t completely overshadow the climate crisis.

Second, he wants to surf on President Obama’s wave of momentum and high popularity. Getting Obama to attend, with the visibility the new president would bring, is a top reason for the summit, according to the unnamed diplomats and U.N. officials quoted in the Reuters story. A Washington Post article went so far as to say “the U.N. chief is planning to shelve the event if the American leader cannot come, according to U.N. diplomats.”

At a press briefing Tuesday morning, Ban said plans for the short-notice summit are underway, though it’s not a done deal. He confirmed he’s been talking climate with the Obama administration, which hasn’t given a public response to the invitation. Ban’s remarks about Obama attendance basically amounted to, “We know you’re busy, but we need you”:

On the question of the involvement of the United States, we should all remind ourselves that President Obama has only been in office for three weeks. I have discussed climate change with President Obama and Secretary Clinton in general terms and look forward to further discussions at the appropriate time. I understand they need to get settled. I know that they are very busy with a national stimulus package.

I can confirm at this time that I am planning to organize a high-level event with Heads of State and Government for all Member States on the margins of the General Assembly in September. The report you have seen these days about possibly convening another high-level summit meeting is now in the process of consulting with countries concerned. Of course, the participation of President Obama will be crucially important. I am going to continue to discuss, to consult on this matter with the U.S. administration. But at this time I understand fully how busily President Obama is engaged in overcoming this national economic crisis, as well as the global financial crisis. I hope that you’ll understand this.

Ban hasn’t said exactly what climate issues need deciding before the September General Assembly meeting, not to mention the COP-15 climate talks scheduled for December in Copenhagen. The Post‘s sources say U.N. officials are worried that government funding for renewable-energy initiatives is on the rocks because of the recession.