Environmental Ministers from the Group of 20 nations were unable to reach full agreement on key climate goals, just 100 days before a critical international conference kicks off.

Even after marathon negotiations that ran through the night, the ministers couldn’t find common ground on phasing out coal or how much to limit global warming, Italy’s Ecological Transition Minister Roberto Cingolani said at a press conference Friday in Naples.

The divisions among the G-20 nations bode badly for United Nations climate talks set to start October 31 in Glasgow. Leaders and diplomats including U.S. presidential climate envoy John Kerry have repeatedly stressed that the meeting, known as COP 26, may be the last chance to set international policies that would prevent the planet from warming more than 1.5 ºC from pre-industrial levels, which scientists say is key to staving off the worst impacts of climate change.

“The G-20 accounts for 80% of all global emissions,” said Patricia Espinosa, head of the UN’s climate change secretariat. “There is no path to 1.5 ºC without the G-20.”

Ending the use of coal, the dirtiest fossil fuel, was a major sticking point. Italy, which is hosting the G-20 meeting, pushed to include that goal within the official communique that will be issued Saturday. However, a number of countries including India and Russia resisted, Cingolani said at the press conference.

The U.S., Canada and Europe were pushing for endorsing the goal of limiting warming to 1.5 degrees. They met pushback from a group of other countries that was unwilling to go beyond the 2015 Paris Agreement’s less ambitious target of 2 degrees.

Cingolani said the nations reached a robust agreement on other fronts despite these areas of divergence, noting that this meeting marked the first time that climate and energy had been dealt with together by the G-20. Areas of disagreement will be addressed in October during the G-20 leaders’ meeting.

This year is seen as a crunch time in climate policy, because all 197 countries in the Paris accord must submit enhanced national plans for cutting emissions. So far only 97 have done so, Espinosa said.

That includes Indonesia, the world’s eighth-largest source of carbon emissions, which submitted a new national plan during the meeting. However, it had the same top-line emissions targets submitted five years ago. Its longer-term goals show that the country plans to peak emissions in 2030 and could reach net-zero greenhouse-gas emissions by 2060 or sooner.

“Indonesia should step up its efforts to address the climate crisis,” Tjokorda Nirarta Samadhi, director of the World Resources Institute’s Indonesia office, said by email. The country should “commit to stop investing in new coal plants and reach zero deforestation by 2030, coupled with substantial reforestation.”