Originally Published: 19 SEP 23 09:32 ET

Updated: 19 SEP 23 10:35 ET

By Caitlin Hu, CNN

United Nations (CNN) — United Nations Secretary-General Antonio Guterres has warned of a looming “Great Fracture” in the world, describing existing global governance structures as failing to serve a changing world.

Speaking before world leaders in the United Nations Assembly Hall on Tuesday, Guterres called for sweeping changes to multilateral institutions, including reforming the powerful Security Council at the heart of the United Nations, and redesigning global financial systems.

“The alternative to reform is not the status quo. The alternative to reform is further fragmentation,” he said. “It’s reform or rupture.

“We are inching ever closer to a Great Fracture in economic and financial systems and trade relations,” he said. “One that threatens a single open Internet, with diverging strategies on technology and artificial intelligence, and potentially clashing security frameworks.”

Guterres described increasing global multipolarity as heralding “new opportunities for justice and balance in international relations” – an acknowledgment of the rise of new powers in the world like India and China, and growing negotiating power of regional blocs. But to ensure peace between nations in a multipolar order, new and strengthened multilateral institutions are all the more important, he added.

The United Nations Security Council and Bretton Woods agreement still reflect the unequal power relations of 1945, Guterres said, “when many countries in this Assembly Hall were still under colonial domination.”

The Security Council is made up of five permanent members – the US, the UK, France, China, Russia – and 10 rotating members. Only one leader from the permanent five members – US President Joe Biden – chose to attend the UN General Assembly this year.

More than 50 UN countries have never been members of the Security Council.

Guterres’ speech hit on long list of smoldering global issues, including bloody violence in Sudan, the Central African Republic, and Haiti; oppression in Myanmar and Afghanistan; and the potential threats of unfettered new technologies, including artificial intelligence.

It also devoted significant attention to climate change, a central issue for Guterres, with the secretary-general taking aim at G20 countries for producing the majority of global emissions amid rising global temperatures, and calling on wealthy nations to deliver billions in promised funding to strengthen developing nations against climate-related threats.

In a notable aside to environmental activists around the world – and on the streets of New York this week – Guterres said, “To all those working, marching and championing real climate action, I want you to know: You are on the right side of history. I’m with you.”

The secretary-general’s address echoed criticisms that he has previously aired of division in the world. In 2021, with parts of the world still gripped by Covid-19, Guterres said the world was “getting an F in ethics.” In 2022, the secretary-general warned the international community was “gridlocked in colossal global dysfunction” – though he pointed to the Black Sea Grain Initiative that opened delivery paths for Ukrainian grain to countries in need as a vital point of hope.

One year later, however, the grain deal has collapsed. And as Russia’s war in Ukraine grinds on, the geopolitical conditions for joint action to stave off humanitarian and environmental disasters can seem further away than ever.

“We have a level of division among superpowers that has no precedent since the Second World War,” Guterres observed in an interview with CNN’s Christiane Amanpour on Monday, ahead of his speech.

All he has to bridge that division, he told Amanpour, is a voice.

“The secretary-general of the United Nations has no power and there’s no money. What we have is a voice. And that voice can be loud. And I have the obligation to make it be loud.”