Leaders of a world fractured by war, climate change and persisting inequality will gather under one roof to hear the UN chief call for united action on humanity's huge challenges.
"People are looking to their leaders for a way out of this mess," secretary-general Antonio Guterres said ahead of Tuesday's annual gathering of presidents and premiers, ministers and monarchs at the General Assembly.
He said the world needs action now - not merely more words - to deal with the worsening climate emergency, escalating conflicts, "dramatic technological disruptions" and a global cost-of-living crisis that is increasing hunger and poverty.
"Yet in the face of all this and more," Guterres said, "geopolitical divisions are undermining our capacity to respond."
This year's week-long session, the first full-on meeting of world leaders since the COVID-19 pandemic disrupted travel, has 145 leaders scheduled to speak.
It is a large number that reflects the multitude of crises and conflicts.
But for the first time in years, US President Joe Biden, who will speak soon after the UN chief, will be the only leader from the five powerful veto-wielding nations on the UN Security Council to address the 193-member assembly.
China's Xi Jinping, Russia's Vladimir Putin, France's Emmanuel Macron and Britain's Rishi Sunak are all skipping the UN this year.
That should put the spotlight on Ukraine's President Volodymyr Zelenskiy, who will be making his first appearance at the assembly's podium later on Tuesday, and on Biden, who will be watched especially for his views on China, Russia and Ukraine.
The G77, the major UN group of developing countries that now has 134 members including China, lobbied hard to make this year's global gathering focus on the 17 UN goals adopted by world leaders in 2015. Those are badly lagging at the halfway point to their 2030 due date.
At a two-day summit to kick-start action to achieve the goals, Guterres pointed to grim findings in a UN report in July. He said 15 per cent of some 140 specific targets to achieve the 17 goals are on track. Many are going in the wrong direction and not a single one is expected to be achieved in the next seven years.
The wide-ranging goals include end extreme poverty and hunger, ensure every child gets a quality secondary education, achieve gender equality and make significant inroads in tackling climate change - all by 2030.
At the current rate, the report said, 575 million people will still be living in extreme poverty and 84 million children will not even be going to elementary school in 2030 - and it will take 286 years to reach equality between men and women.
Guterres told leaders at Monday's opening of the summit he called to rescue the 17 sustainable development goals (SDGs) that they promised in 2015 to build "a world of health, progress and opportunity" for all people - and to pay for it.
Soon after he spoke, leaders from the 193 UN member nations adopted a 10-page political declaration by consensus which recognises that the goals are "in peril". But it reaffirms more than a dozen times, in different ways, leaders' commitment to achieve the SDGs, reiterating their individual importance.