The world is becoming unhinged as geopolitical tensions rise and it seems incapable of coming together to respond to mounting challenges, the UN secretary general, António Guterres, has said in his speech opening the UN general assembly in New York. He said global governance was “stuck in time” at a point when strong, modern, multilateral institutions were in greater need than ever. Reflecting on a year in which the UN has seemed paralysed by divisions over the war in Ukraine, Guterres put those divisions in a broader context. “We cannot effectively address problems as they are if institutions don’t reflect the world as it is. Instead of solving problems, they risk becoming part of the problem,” he said, adding that divides were deepening “among economic and military powers, and between north and south, east and west”. He said the world was “inching ever closer to a great fracture in economic and financial systems and trade relations; one that threatens a single, open internet; with diverging strategies on technology and artificial intelligence; and potentially clashing security frameworks”. Guterres has been criticised for issuing a series of arresting but increasingly dark warnings about the plight of the world, so his aides stressed that his speech, while candid about the challenges, was one of his most “solution heavy”. He called for deep reforms of the “dysfunctional, outdated and unjust international financial architecture”, including a $500bn-a-year rescue package for countries most heavily in debt. On the climate crisis, he demanded a climate solidarity pact in which all big emitters make extra efforts to cut emissions and wealthier countries support emerging economies with finance and technology to do so. “Africa has 60% of the world’s solar capacity but just 2% of renewable investments,” he pointed out. Guterres called for “an end to coal – by 2030 for OECD countries and 2040 for the rest of the world”. He said the floods in Libya were “a snapshot of the state of our world” and a sign of what happens when climate change meets poor governance. “Victims of years of conflict, victims of climate chaos, victims of leaders – near and far – who failed to find a way to peace,” he said of those who died in the floods. “The people of Derna lived and died in the epicentre of that indifference – as the skies unleashed 100 times the monthly rainfall in 24 hours … as dams broke after years of war and neglect.” Guterres broke newer policy ground by putting artificial intelligence – something he described as a subject of awe and fear – at the heart of the UN agenda, confirming he was appointing a high-level panel to report to him on its implications by the end of the year. He suggested a new global entity on AI that could provide a source of information and expertise for member states, equivalent to the Intergovernmental Panel on Climate Change. He was more unequivocal than sometimes in his condemnation of Russia’s invasion of Ukraine and its wider ramifications. “If every country fulfilled its obligations under the UN charter, the right to peace would be guaranteed. When countries break those pledges, they create a world of insecurity for everyone. Exhibit A: Russia’s invasion of Ukraine,” he said. “The war, in violation of the United Nations charter and international law, has unleashed a nexus of horror: lives destroyed; human rights abused; families torn apart; children traumatised; hopes and dreams shattered,” he said. “Beyond Ukraine, the war has serious implications for us all. Nuclear threats put us all at risk. Ignoring global treaties and conventions makes us all less safe. And the poisoning of global diplomacy obstructs progress across the board. Calling for a broadening of the UN security council, which has been on the agenda for decades, Guterres said the world was in a state of chaotic transition and had to return to the art of compromise. “I have no illusions. Reforms are a question of power. I know there are many competing interests and agendas. But the alternative to reform is not the status quo. The alternative to reform is further fragmentation. It’s reform or rupture,” he said. The Brazilian president, Luiz Inácio Lula da Silva, followed Guterres by staking his claim to be the true leader of the global south, telling the UN that market liberalism had plagued democracy and disfranchised millions, leaving them in poverty and prey to nationalist totalitarianism. “The 10 richest billionaires have more wealth than the poorest 40% of humanity,” he said, adding that there was a lack of political will among those who governed the world “to overcome inequality”. He made no direct criticism of Vladimir Putin but said the UN was losing credibility and blamed this frailty on “the specific result of actions from its permanent members who wage unauthorised wars aimed at territorial expansion or regime change. Its paralysis is the most eloquent proof of the urgent need to reform it.” Lula has come under criticism for saying he would welcome Putin to Brazil, for questioning the role of the international criminal court and for failing to meet the Ukrainian president, Volodymyr Zelenskiy, an omission he is due to rectify in New York on Wednesday. Setting out what he said would be Brazil’s agenda for its upcoming G20 presidency, he offered a vision that was explicitly more socialist than the one provided by Narendra Modi, the Indian prime minister and outgoing G20 chair. “Government’s need to break away from the increasing dissonance between the voice of the markets and the voice of the streets,” he said. “Neoliberalism has aggravated the economic and political inequality that plagues democracies today. Its legacy is a mass of disfranchised and excluded people.” He said vulnerable populations in the global south were most affected by the loss and damage caused by the climate crisis while the richest 10% of the world’s population were responsible for almost half of all carbon released into the atmosphere. “We developing countries do not want to repeat this model,” he said. Amid reports that Brazil will tighten its own greenhouse gas emissions, he said the Amazon was already speaking for itself, and over the past eight months deforestation had been reduced by 48%.