Countries must honour the commitments they made last week at the Cop26 talks, conference President Alok Sharma said as the business end of the negotiations looms.
The UN climate talks are entering their second week with ministers arriving for the political stage of the negotiations, while Monday will also focus on support for poorer countries to cope with climate change.
Mr Sharma said finding consensus among almost 200 countries, which is needed for agreement under the UN climate system, was not going to be straightforward.
But he said progress last week demonstrated a “constructive spirit” among negotiators.
The announcements countries made last week are not necessarily included in their national plans for action this decade, which leave the world far off track on meeting the goal of trying to limit global warming to 1.5°C above pre-industrial levels.
Negotiators are trying to hammer out a “cover decision” from Glasgow that will set out how they will close the gap between plans to cut emissions this decade and what is needed to avoid temperature rises of more than 1.5°C.
Vulnerable countries are pushing for nations to revisit their nationally determined contributions annually to close the gap, but others are opposed to speeding up the process from its five-yearly cycle.
“Here in Glasgow we have a unique opportunity to reach a historic outcome and I am committed to bringing countries together to forge an agreement that means we see more action this decade, which helps to keep the 1.5°C temperature limit within reach,” Mr Sharma said.
He said there was a need for urgency in the negotiations.
“Last week, countries made commitments which will all help to protect our planet but they must be delivered on and accounted for,” Mr Sharma said.
Making sure countries increase their ambitions this decade is one of the issues up for debate, along with finance for poorer countries to develop cleanly and cope with climate impacts, and funding for them to deal with loss and damage.
Ministers also need to negotiate the last parts of the Paris Agreement, under which countries agreed in 2015 to limit temperature rises to “well below” 2°C, to make it operational.
Former US president Barack Obama, a veteran of the failed UN climate summit in Copenhagen and the successful meeting in Paris that secured the world’s first comprehensive climate treaty, will be at a series of events in Glasgow.
They include a speech laying out the progress made in the five years since the Paris Agreement took effect, highlighting the leadership of young people around the globe, and urging stronger action from governments, the private sector, philanthropy and civil society.
Mr Obama will also meet young leaders attending Cop26 to discuss how their generation is leading the fight against climate change.