The second round of UN climate talks in 2010 started in Bonn Monday, focusing on issues that remained unsolved in Copenhagen and paving the way for the Cancun meeting in Mexico in December.

The 32nd session of the UN Framework Convention on Climate Change will last till June 9, while the 12th session of the Ad hoc Working Group on the Kyoto Protocol (AWG-KP) and 10th session of the Ad hoc Working Group on Long-term Cooperation Action (AWG-LCA) will take place from Tuesday to June 11.

The Bonn gathering is attended by more than 4,500 participants from governments, business, industry, environmental organizations and research institutions in 182 countries.

The June session will be the first since last December's contentious Copenhagen conference for participants to have serious and substantive talks. The talks are expected to focus on a draft text for the Cancun meeting to start negotiation with.

"Climate negotiations over the next two weeks will be on track if they keep focusing on a common way forward towards a concrete and realistic goal in Cancun. There is a growing consensus on what the goal for Cancun can be -- namely, a full, operational architecture to implement effective and collective climate action," said top UN climate change official Yvo de Boer.

The 12th session of the AWG-KP will focus on emissions reduction commitments for the 37 industrialized countries that indicated their intention of throwing out the Kyoto Protocol.

"I encourage governments to now develop greater clarity on the future of the Kyoto Protocol, since this issue cannot be left unattended until Cancun," de Boer said.

The UN climate change official also called on industrialized countries to fulfill the financial pledge of 30 billion U.S. dollars they made at Copenhagen.

"Cancun can deliver if promises of help are kept and if promises to compromise are honored in the negotiations," he said.

"Recent pledges by Spain and Germany towards the adaptation fund are useful first steps to build trust among developing nations," said de Boer, adding that more concrete contributions are needed.