Transparency divides countries in Copenhagen

Transparency, or making sure developing countries' emission cuts are properly monitored and verified, emerged on Thursday as a major stumbling block in UN climate negotiations. This issue epitomises the mistrust between rich and poor countries.

The US tried to inject fresh momentum into the talks as heads of state and ministers finally entered into substantive discussions on Thursday afternoon, with Secretary of State Hillary Clinton announcing she was prepared to help raise $100bn a year by 2020 for developing countries.

But Mrs Clinton listed several conditions, including international monitoring, reporting and verification (MRV) rules for developing countries' domestically-funded mitigation actions, which China explicitly rejected shortly after. Full transparency is "a kind of deal-breaker" for the US, Mrs Clinton said.

Both the US and China's vice foreign minister He Yafei said the summit had reached a "critical junction" on Thursday afternoon following a standstill since Wednesday morning. The talks were unblocked when Denmark agreed not to table a fresh set of draft negotiating texts.

Developing countries had vehemently rejected Denmark's plans to issue new, stripped-down versions of texts under the UNFCCC and Kyoto protocol negotiating tracks, insisting the talks must work with draft UN texts prepared by all parties earlier in the week.

After Denmark agreed to this on Thursday morning, two contact groups were set up, one under each negotiating track. The UNFCCC group was subsequently split into 11 sub-groups and the Kyoto group into five sub-groups, which met on Thursday afternoon. All were due to report back by the evening.

Meanwhile, the difficult issue of bunker fuels, which UN climate chief Yvo de Boer had reportedly declared "dead" on Tuesday night, resurfaced in a sub-group under the UNFCCC negotiating track. But green transport group T&E said the draft text circulating was very weak.

• Climate