"While this is an important step, it is only a first step," he told reporters. "A beginning and not an end."
Ban said he would hold a meeting of leaders at the United Nations in New York on Sept. 24, a day before the general assembly convenes, to move the process forward before the start of talks on a new framework climate change agreement in Bali, Indonesia at the end of the year.
"This meeting will represent an important, preparatory step for achieving real progress to launching negotiations at ... the meeting in Bali in December," he said.
Ban said the decision to pursue an agreement under the framework of the United Nations was the right course of action, given its wide reach and access to experts.
"We have an ever expanding arsenal of technologists to address the threat and also have significant resources at our disposal," he said.
But "what we are desperately in need of at this time is political will at the leaders' level to make significant emission reductions and to help countries to adapt to climate change," Ban said, adding "we will need leadership by the G-8 countries."
He said addressing climate change will mean finding a common ground to utilize the various paths available, from new technology to conservation efforts to improving land use practices.
The important thing, he said, "that these policies be complementary and mutually reinforcing. The many strengths must be woven into one cloth."