US President Joe Biden on Friday urged the world to bring its "highest" ambition to a UN summit on climate change in November, warning that the planet faces a tightening deadline.

"We have to bring to Glasgow our highest ambitions. Those who have not yet done so, time is running out," Biden said in the White House at the start of a virtual summit with nine foreign leaders.

Biden said the United States was taking concrete steps toward UN climate goals but noted that recent devastating flooding in the US northeast and wildfires in western states echoed extreme weather events from China to the Amazon.

Last month, the UN's Intergovernmental Panel on Climate Change said the Earth's average global temperature will reach 1.5 degrees Celsius above pre-industrial levels around 2030, a decade earlier than projected three years ago.

Biden said this represents "a code red for humanity" and that "we have to act, all of us, we have to act now."

Biden called the virtual forum -- where there were notable absences of Chinese President Xi Jinping and the leaders of Brazil and India -- in preparation for the major UN summit taking place in Glasgow at the start of November.

US President Joe Biden holds a virtual meeting with leaders on climate change
US President Joe Biden holds a virtual meeting with leaders on climate change AFP / MANDEL NGAN

World leaders will also be attending a separate closed-doors climate conference on Monday on the sidelines of the annual UN General Assembly in New York.

The Glasgow summit is focused on ensuring the world sticks to an agreed goal of limiting warming to 1.5 degrees Celsius.

But "without adequate commitments from every nation in this room, the goal of limiting warming to 1.5 slips through our hands and that is a disaster," Biden said.

He noted the US commitment to reduce greenhouse gas emissions by between 50 and 52 percent by 2030 compared with 2005 levels, along with several other hefty targets.

One of these is a joint pledge with the European Union and other partners to reduce global methane emissions by at least 30 percent below 2020 levels by 2030.

"Our emphasis this year is going to be on building ambition on the road to Glasgow," he said, but "Glasgow is not our final destination."

Attending the White House meeting by video link were the presidents of Argentina, Bangladesh, Indonesia, Mexico, South Korea, Britain's Prime Minister Boris Johnson, UN Secretary General Antonio Guterres, European Council President Charles Michel, and EU Commission President Ursula von der Leyen.