Conceding that the climate change deal reached in Copenhagen did not go far enough, UN chief Ban Ki-moon on Monday urged world leaders to clinch a legally binding treaty next year.
"I am aware that the outcome of the Copenhagen conference, including the Copenhagen Accord, did not go as far as many would have hoped," Ban told reporters at UN headquarters on his return from the Danish capital.
"Nonetheless they represent a beginning, an essential beginning... We have taken an important step in the right direction," he added.
Ban pressed all world leaders "to directly engage in achieving a global legally binding climate change treaty in 2010" and said the challenge for the UN was to marshal the necessary political will and translate it into action.
The UN boss said he would early next year set up a high-level panel on development and climate change to address those issues.
The agreement in Copenhagen was assembled by the leaders of the United States, China, India, Brazil, South Africa and major European nations, after it became clear the 194-nation summit was in danger of failure.
It promised 100 billion dollars for poor nations that risk bearing the brunt of the global warming fallout and set a commitment to limit global warming to two degrees Celsius (3.6 degrees Fahrenheit).
Now negotiators and NGOs alike are pinning their hopes on the next big climate rendezvous a year from now, in Mexico City.
The goal is to sign a treaty in Mexico City in December 2010 and have it take effect from 2013, after the current roster of pledges under the UN's Kyoto Protocol expire.
The UN's Nobel-winning Intergovernmental Panel on Climate Change (IPCC) has warned that voracious use of coal and other fossil fuels will see planetary warming of up to 6.4 degress Celsius by 2100 unless carbon pollution was deeply slashed.
Scientists say hundreds of millions of people are threatened in the next few decades by worsening drought, floods, storms and rising sea levels as a result of rising temperatures.