**High-level talks at the UN climate summit have opened, with UN chief Ban Ki-moon telling nations to “seal a deal” on climate change.**He told delegates in Copenhagen that they had the chance to change history.
But he added: “We do not have another year to deliberate; nature does not negotiate with us.”
Earlier, a senior UN official warned that negotiations were progressing too slowly and that there was still an “enormous amount of work to be done”.
Delegates have been poring over the details of a new draft text, ahead of the start of the high-level segment.
On Friday, about 130 world leaders are set to attend the summit’s final session.
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