Countries should impose windfall taxes on fossil fuel companies and divert the money to vulnerable nations suffering worsening losses from the climate crisis, the United Nations secretary general has urged.

António Guterres said that “polluters must pay” for the escalating damage caused by heatwaves, floods, drought and other climate impacts, and demanded that it was “high time to put fossil fuel producers, investors and enablers on notice”.

“Today, I am calling on all developed economies to tax the windfall profits of fossil fuel companies,” Guterres said in a speech to the UN general assembly on Tuesday. “Those funds should be redirected in two ways – to countries suffering loss and damage caused by the climate crisis and to people struggling with rising food and energy prices.”

Guterres’s appeal came in his most urgent, and bleakest, speech to date on the state of the planet, and the will of governments to change course.

His first words were: “Our world is in big trouble.”

“Let’s have no illusions. We are in rough seas. A winter of global discontent is on the horizon, a cost-of-living crisis is raging, trust is crumbling, inequalities are exploding and our planet is burning,” he told the assembly. “We have a duty to act and yet we are gridlocked in colossal global dysfunction. The international community is not ready or willing to tackle the big dramatic challenges of our age.”

The lacerating speech, delivered at the UN headquarters in New York, echoes calls from activists, and the European Union, to tax major oil and gas firms currently enjoying record profits in the wake of Russia’s invasion of Ukraine. In July, Exxon announced it had made a record quarterly profit of $17.8bn, while Chevron unveiled its own three-month record profit, of $11.6bn. BP, meanwhile, made a $8.5bn profit in the same period.

Under Guterres’s proposal, revenue from the taxes would flow to predominantly developing countries suffering “loss and damage” from global heating, to be invested in early warning systems, mopping up from disasters and other initiatives to build resilience. Vulnerable countries are poised to leverage the UN general assembly week to ask rich nations for a “climate-related and justice-based” global tax to pay for loss and damage.