The United Nations secretary general has warned that the world is “on the edge of an abyss and moving in the wrong direction” in an urgent and sometimes angry address to the world’s leaders at the UN general assembly (Unga).

Antonio Guterres painted a stark picture of unsustainable inequalities, runaway climate change and feckless leadership.

“I’m here to sound the alarm. The world must wake up,” Guterres said.

He pointed to the current gross inequalities in the global distribution of vaccines, with large majorities in the rich world already vaccinated while over 90% of Africans were still waiting for their first dose.

“This is a moral indictment of the state of our world. It is an obscenity,” the secretary general said. He talked about vast disparities in wealth that saw “billionaires joyride into space while millions go hungry”, side by side with the retreat of democracy.

“We are seeing an explosion in seizures of powers by force. Military coups are back,” he said. When democracies fail to deliver the basic needs of their people, Guterres added: “It provides oxygen for easy fixes, silver solutions and conspiracy theories”.

It is customary for secretaries general to urge the leaders gathered in New York for Unga to do better for their people. Guterres has scolded them before, but this year’s speech from the green marble podium was particularly bleak.

On the climate emergency, Guterres said the world was sleepwalking to disaster, noting that if all coal power stations planned around the world become operational, the planet’s average temperature will rise by well over 2C.

“This is a planetary emergency,” he said. “We are on the edge of an abyss – and moving in the wrong direction. Our world has never been more threatened, or more divided.”

Without naming the US and China, he said their superpower rivalry threatened any hope of progress in addressing the world’s problems.

“It will be impossible to address the dramatic economic and development challenges, while the world’s two largest economies are at odds with each other,” he said. “I feel our world is slipping towards two different sets of economic trade, financial and technological rules, two divergent approaches in the development of artificial intelligence, and ultimately, the risk of different military and geopolitical strategies, and this is a recipe for trouble. It will be far less predictable than the cold war.”

“To restore trust, and inspire hope, we need cooperation, we need dialogue, we need understanding,” the secretary general said, but little if anything in the litany of disastrous problems and bad choices he laid out suggested that any of those virtues would be on display in the coming few days in New York.