Christiana Figueres, the executive secretary of the United Nations Framework Convention on Climate Change (UNFCCC), Tuesday called for all signatories' "reconciliation" to reach concrete agreements to combat climate change.

In a ceremony that formally opened the plenary of the 16th UNFCCC Conference of the Parties (COP16), Figuieres asked those present to seek "common ground" and unity.

"We must return to the path and that can only be achieved by leaving behind national interests," Figueres said, "We have to find common ground, because we all depend on this planet which is now fragile."

"The only way to reach this goal is reconciling everyone -- that is our task here -- above all the elements that remain to be solved from the Bali Road Map," she said.

One of the key difficulties at the COP16 is to agree on a second commitment period for the Kyoto Protocol, which commits signatories to cutting emissions by 5 percent from their 1990 levels by 2012.

The signatories have to reach an appropriate agreement on mitigation, the reduction of emissions worldwide.

"There must be a reconciliation in accountability and financial support and a negotiation on justice, on mitigation," Figueres said.

She added that signatories had explored positions which were outside their national position during last week's preparatory meetings in Cancun, and asked those signatories not to ask for a windfall but to think of the planet and "offer their windfall first."

"Cancun must produce results. The world will be watching what you do here," Figueres urged. During the four-day meeting, the UNFCCC's 194 signatories must grapple with the world's most complex issues.

On the Kyoto Protocol, Japan, Russia and Canada oppose a new commitment period, while a group of 77 nations, which includes the four largest developing economies -- China, South Africa, India and Brazil, are determined not to sign any climate deal until Kyoto is agreed upon.