UN Secretary-General Antonio Guterres delivers a speech at a UN high-level event on Climate Action and the Just Transition at the UN headquarters in New York, on Sept. 23, 2026. Guterres on Wednesday urged efforts to increase financial support and strengthen cooperation in global climate action. (Xinhua/Wu Xiaoling)

UN Secretary-General Antonio Guterres on Wednesday urged efforts to increase financial support and strengthen cooperation in global climate action.

"The world is crying out for climate justice -- in mitigation, in adaptation, in finance. We must answer that call with action. And we don't have a moment to lose," Guterres said in a speech at a UN high-level event on Climate Action and the Just Transition.

Guterres called on every country to "develop a credible roadmap to transition away from fossil fuels with clear timelines," highlighting the importance of international cooperation on global climate action.

The G20 group, responsible for 80 percent of global emissions, must take the lead, he said, while developing countries must not be sidelined from decision-making.

"The principle of common but differentiated responsibilities must apply," he noted.

Guterres stressed the need for robust financial support for the transition from fossil fuels to renewable energy.

This includes mobilizing at least 300 billion U.S. dollars annually for developing countries, scaling up climate finance to 1.3 trillion dollars per year by 2035, reforming the international financial architecture to give developing countries a greater role, and making multilateral development banks "bigger, bolder and better."

"We are the first generation with the tools to end the fossil fuel age, and the last who can avert climate catastrophe. Let us use them well," the UN chief said.