The UN secretary-general has warned negotiators at a major meeting that failing to increase efforts on climate change would be "not only immoral but suicidal" for the planet.
Antonio Guterres has flown back to Poland to try and push COP24 to a successful conclusion.
At the UN talks, a group of countries have said they will enhance their climate plans before 2020. The EU and others say they are responding to the urgency of science.
Some observers believe that the return of Mr. Guterres to these talks is a sign that significant progress is not being made.
In his remarks to the conference, he underlined that fact, imploring the delegates to speed up the pace of negotiations and to be open to compromise.
He said that key political issues here in Poland remain unresolved.
"To waste this opportunity would compromise our last best chance to stop runaway climate change," Mr Guterres said. "It would not only be immoral, it would be suicidal."
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What's worrying many delegates and observers here is the complexity of the task of delivering a strong rulebook on the Paris pact.
There is a fear among some delegates that ministers who are here to make the final political decisions on the outstanding issues may oversimplify the situation.
There are still outstanding questions over how to have a single set of rules for every country that is flexible enough to not overwhelm poorer nations with huge amounts of red tape.
Source: Radio Pakistan