Andre Correa do Lago, a veteran climate diplomat tapped to lead the November conference, also vowed to campaign for greater climate funding for poorer nations in a closely-watched speech that did not mention fossil fuels.

COP30 in the Amazonian city of Belem marks a decade since the signing of the Paris Agreement, but follows the second US withdrawal from the landmark pact and other global efforts to address climate change.

There are concerns that climate change is being crowded out of the global agenda by national security and economic pressures.

A finance deal for developing nations brokered at the last COP in Azerbaijan was slammed as inadequate, while other global conservation efforts have stalled, including negotiations towards a plastic treaty.

Corporations, too, are rolling back pledges to cut their carbon footprints.

Correa do Lago said that November's COP30 would be an opportunity to advance and defend the climate agreements forged through years of cooperation and negotiation to tackle this "shared global crisis".

"In a time of serious geopolitical, social, economic and environmental challenges... we must reinforce multilateralism," he told the Petersberg Climate Dialogue, the first major COP30-related meeting of the year.

German Foreign Minister Annalena Baerbock, without naming any countries, told attendees that the Paris accord was "coming under pressure once again".

"Anyone who dismisses climate action in these turbulent times as being expensive, onerous or superfluous, cannot count," she said.

- 'Join forces' -

Correa do Lago said governments "must do their part in this global effort" by unveiling stronger 2030 targets for cutting domestic greenhouse gas emissions.

Most countries -- including major emitters China, Europe, and India -- missed the deadline in February to submit these national climate plans.

But businesses also have "a crucial role to play" and must "contribute significantly" in shifting the global economy to a low-carbon future, he said.

The private sector would be essential to raise the $1.3 trillion a year in external finance that developing nations will need by 2035 to meet their climate needs, Correa do Lago added.

He also urged nations to "join forces" to keep global warming to 1.5 degrees Celsius above pre-industrial levels, the safer limit of the Paris accord.

But the COP30 president made no mention of fossil fuels, the key driver of global warming, despite nations agreeing in 2023 to transition away from oil, coal and gas.

Critics say this pledge has not been honoured, and emissions of heat-trapping gases from burning fossil fuels hit fresh highs in 2024.

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