GLASGOW, Scotland (AP) — United Nations Secretary-General Antonio Guterres says the goal of limiting global warming to 1.5 degrees Celsius (2.7 F) is “on life support” with climate talks in Glasgow so far not reaching any of the U.N.’s three goals, but he added that “until the last moment, hope should be maintained.”

In an exclusive interview Thursday with The Associated Press, Guterres said the U.N. climate talks in Glasgow, Scotland “are in a crucial moment” and need to accomplish more than securing a weak deal that participating nations agree to support.

“The worst thing would be to reach an agreement at all costs by a minimum common denominator that would not respond to the huge challenges we face,” Guterres said.

That’s because the overarching goal of limiting warming since pre-industrial times to 1.5 degrees Celsius (2.7 F) by the end of the century “is still on reach but on life support,” Guterres said. The world has already warmed 1.1 degrees Celsius (2 degrees Fahrenheit), leaving less than a degree before the threshold is hit.

“It is the moment to reach agreement by increasing ambition in all areas: mitigation, adaptation and finance in a balanced way,” Guterres said in the 25-minute AP interview.

A U.S.-China agreement announced Wednesday provided some hope of the negotiations yielding significant progress.

Officials from almost 200 nations worked through the night at the UN climate talks in Glasgow, trying to hammer out agreements on a range of tricky topics in time for a Friday deadline.

Among the outstanding issues was international carbon trading, a subject that has nagged at negotiators since the landmark Paris climate accord was sealed in 2015.

“We’re still at the stage of options,” a European negotiator told The Associated Press on Thursday. “But it’s moving forward. We still need that push though.”

The official spoke on condition of anonymity because he wasn’t authorised to be quoted.

Fresh drafts of the documents on regulating international cooperation to reduce greenhouse gas emissions, including the carbon markets section, were released overnight, as were new proposals containing various options for assessing and tracking financial aid for developing countries.

Poor nations have insisted they will not back any deal that fails to address their need for funds to help cut emissions and adapt to the consequences of global warming, a problem they have contributed least to.

Negotiators were hoping that a bilateral agreement Wednesday between the United States and China to cooperate in tackling climate change would provide a boost during the final hours of the talks.

British Prime Minister Boris Johnson on Wednesday urged fellow world leaders to call their negotiating teams in Glasgow and give them the political backing to clinch an ambitious deal.

Officials and observers have said the bar for success must be a strong affirmation of the Paris goal of keeping global warming well below 2 degrees Celsius (3.6 degrees Fahrenheit) — ideally no more than 1.5 C (2.7 F) =- backed by credible policies from all nations to get there. So far, scientists say the world is not on track for that.