Now is the time to be ambitious, show leadership and ignore the naysayers on the issue of climate change. This was the message of UN Secretary-General Ban Ki-Moon and South African President Jacob Zuma, when they addressed world leaders at the Cop-17 talks, in Durban, South Africa. They also called on parties at the Climate Change Talks not to disappoint the world's citizens.

COP 17 President Maite Nkoana-Mashabane speaks during a press conference with Executive Secretary of the United Nations Framework Convention on Climate Change (UNFCCC) Christiana Figueres (L) at the Conference of the Parties (COP17) of the United Nations Climate Change Conference in Durban, November 30, 2011.

The High Level Segment of the Durban Climate Change Conference got underway with a special welcome for the more than 100 ministers and 12 heads of state, who now have the task of working on balanced, fair and credible solutions for a future Climate Change regime.

UN Secretary-General Ban Ki-Moon said global economic problems meant that it may not be realistic to expect a legally-binding outcome in Durban.

But he urged Climate Change negotiators and political leaders to keep up their momentum, in their crucial discussions over the next few days.

President Jacob Zuma called on leaders to forgo their national interests in the interest of humanity.

Speaking on behalf of the bloc of developing Basic countries, China's Chief negotiator, said the four countries - Brazil, India, China and South Africa - spoke with one voice on the issue of climate change.